fathers of biology, by charles mcrae

7/31/2019 Fathers of Biology, By Charles McRae

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Fathers

of

BiologybyCharles McRae, M.A., F.L.S.

formerly scholar of Exeter College, Oxford


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Table of Contents

Preface.

Hippocrates.

Aristotle.

Galen.Vesalius.

Harvey.

Index.
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Preface

It is hoped that the account given, in thefollowing pages, of the lives of five greatnaturalists may not be found devoid of interest.The work of each one of them marked a definiteadvance in the science of Biology.

There is often among students of anatomyand physiology a tendency to imagine that thefacts with which they are now being madefamiliar have all been established by recentobservation and experiment. But even the slight

knowledge of the history of Biology, which maybe obtained from a perusal of this little book, willshow that, so far from such being the case, thisbranch of science is of venerable antiquity. And,further, if in the place of this misconception adesire is aroused in the reader for a fuller

acquaintance with the writings of the earlyanatomists the chief aim of the author will havebeen fulfilled.


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Hippocrates

Owing to the lapse of centuries, very little isknown with certainty of the life of Hippocrates,who was called with affectionate veneration byhis successors the divine old man, and who has

been justly known to posterity as the Father ofMedicine.

He was probably born about 470 B.C., and,according to all accounts, appears to havereached the advanced age of ninety years or

more. He must, therefore, have lived during aperiod of Greek history which was characterizedby great intellectual activity; for he had, as hiscontemporaries, Pericles the famous statesman;the poets schylus, Sophocles, Euripides,Aristophanes, and Pindar; the philosopher

Socrates, with his disciples Xenophon and Plato;the historians Herodotus and Thucydides; andPhidias the unrivalled sculptor.

In the island of Cos, where he was born,stood one of the most celebrated of the templesof sculapius, and in this templebecause he


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was descended from the AsclepiadHippocrates inherited from his forefathers an

important position. Among the Asclepiads thehabit of physical observation, and even manualtraining in dissection, were impartedtraditionally from father to son from the earliestyears, thus serving as a preparation for medicalpractice when there were no written treatises tostudy.1

Although Hippocrates at first studiedmedicine under his father, he had afterwards forhis teachers Gorgias and Democritus, both ofclassic fame, and Herodicus, who is known as thefirst person who applied gymnastic exercises tothe cure of diseases.

The Asclepions, or temples of health, wereerected in various parts of Greece as receptaclesfor invalids, who were in the habit of resorting tothem to seek the assistance of the god. These

temples were mostly situated in theneighbourhood of medicinal springs, and eachdevotee at his entrance was made to undergo aregular course of bathing and purification.Probably his diet was also carefully attended to,and at the same time his imagination was worked

upon by music and religious ceremonies. On his
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departure, the restored patient usually showedhis gratitude by presenting to the temple votive

tablets setting forth the circumstances of hispeculiar case. The value of these to men about toenter on medical studies can be readilyunderstood; and it was to such treasures ofrecorded observationscollected during severalgenerationsthat Hippocrates had access fromthe commencement of his career.

Owing to the peculiar constitution of theAsclepions, medical and priestly pursuits had,before the time of Hippocrates, becomecombined; and, consequently, although rationalmeans were to a certain extent applied to thecure of diseases, the more common practice wasto resort chiefly to superstitious modes ofworking upon the imagination. It is notsurprising, therefore, to find that every sickness,especially epidemics and plagues, were attributedto the anger of some offended god, and that

penance and supplications often took the place ofpersonal and domestic cleanliness, fresh air, andlight.

It was Hippocrates who emancipatedmedicine from the thraldom of superstition, and

in this way wrested the practice of his art from


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As an additional argument against the causebeing divine, he adduces the fact that this disease

is hereditary, like other diseases, and that itattacks persons of a peculiar temperament,namely, the phlegmatic, but not the bilious; andyet if it were really more divine than the others,he justly adds, it ought to befall all alike.

Again, speaking of a disease commonamong the Scythians, Hippocrates remarks thatthe people attributed it to a god, but that to meit appears that such affections are just as muchdivine as all others are, and that no one disease iseither more divine or more human than another,but that all are alike divine, for that each has itsown nature, and that no one arises without anatural cause.

From this it will be seen that Hippocratesregarded all phenomena as at once divine andscientifically determinable. In this respect it is

interesting to compare him with one of his mostillustrious contemporaries, namely, withSocrates, who distributed phenomena into twoclasses: one wherein the connection ofantecedent and consequent was invariable andascertainable by human study, and wherein

therefore future results were accessible to a well-


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instructed foresight; the other, which the godshad reserved for themselves and their

unconditional agency, wherein there was noinvariable or ascertainable sequence, and wherethe result could only be foreknown by someomen or prophecy, or other special inspiredcommunication from themselves. Each of theseclasses was essentially distinct, and required tobe looked at and dealt with in a manner radicallyincompatible with the other. Physics andastronomy, in the opinion of Socrates, belongedto the divine class of phenomena in which humanresearch was insane, fruitless, and impious.2

Hippocrates divided the causes of diseasesinto two classes: the one comprehending theinfluence of seasons, climates, water, situation,and the like; the other consisting of such causesas the amount and kind of food and exercise inwhich each individual indulges. He consideredthat while heat and cold, moisture and dryness,

succeeded one another throughout the year, thehuman body underwent certain analogouschanges which influenced the diseases of theperiod. With regard to the second class of causesproducing diseases, he attributed many disordersto a vicious system of diet, for excessive and


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defective diet he considered to be equallyinjurious.

In his medical doctrines Hippocrates startswith the axiom that the body is composed of thefour elementsair, earth, fire, and water. Fromthese the four fluids or humours (namely, blood,phlegm, yellow bile, and black bile) are formed.Health is the result of a right condition andproper proportion of these humours, diseasebeing due to changes in their quality ordistribution. Thus inflammation is regarded asthe passing of blood into parts not previouslycontaining it. In the course of a disorderproceeding favourably, these humours undergospontaneous changes in quality. This process isspoken of as coction, and is the sign of returninghealth, as preparing the way for the expulsion ofthe morbid mattersa state described as thecrisis. These crises have a tendency to occur atcertain periods, which are hence called critical

days. As the critical days answer to the periods ofthe process of coction, they are to be watchedwith anxiety, and the actual condition of thepatient at these times is to be compared with thestate which it was expected he ought to show.From these observations the physician may

predict the course which the remainder of the


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disease will probably take, and derive suggestionsas to the practice to be followed in order to assist

Nature in her operations.

Hippocrates thus appears to have studied thenatural history of diseases. As stated above, hispractice was to watch the manner in which thehumours were undergoing their fermentingcoction, the phenomena displayed in the criticaldays, and the aspect and nature of the criticaldischargesnot to attempt to check the processgoing on, but simply to assist the naturaloperation. His principles and practice were basedon the theory of the existence of a restoringessence (or ) penetrating through allcreation; the agent which is constantly striving topreserve all things in their natural state, and torestore them when they are preternaturallyderanged. In the management of this vismedicatrix natur the art of the physicianconsisted. Attention, therefore, to regimen and

diet was the principal remedy Hippocratesemployed; nevertheless he did not hesitate, whenhe considered that occasion required, toadminister such a powerful drug as hellebore inlarge doses.


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The writings which are extant under the name ofHippocrates cannot all be ascribed to him. Many

were doubtless written by his family, hisdescendants, or his pupils. Others areproductions of the Alexandrian school, some ofthese being considered by critics as wilfulforgeries, the high prices paid by the Ptolemiesfor books of reputation probably having acted asinducements to such fraud. The following workshave generally been admitted as genuine:

1. On Airs, Waters, and Places.2. On Ancient Medicine.3. On the Prognostics.4. On the Treatment in Acute Diseases.5. On Epidemics [Books I. and III.].6. On Wounds of the Head.7. On the Articulations.8. On Fractures.9. On the Instruments of Reduction.10. The Aphorisms [Seven Books].

11. The Oath.

The works On Fractures, On theArticulations, On Injuries to the Head, andOn the Instruments of Reduction, deal withanatomical or surgical matters, and exhibit a

remarkable knowledge of osteology and anatomy


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generally. It has sometimes been doubted ifHippocrates could ever have had opportunities of

gaining this knowledge from dissections of thehuman body, for it has been thought that thefeeling of the age was diametrically opposed tosuch a practice, and that Hippocrates would nothave dared to violate this feeling. The languageused, however, in some passages in the work Onthe Articulations, seems to put the matterbeyond doubt. Thus he says in one place, But ifone will strip the point of the shoulder of thefleshy parts, and where the muscle extends, andalso lay bare the tendon that goes from thearmpit and clavicle to the breast, etc. And again,further on in the same treatise, It is evident,then, that such a case could not be reduced eitherby succussion or by any other method, unless onewere to cut open the patient, and then, havingintroduced the hand into one of the greatcavities, were to push outwards from within,which one might do in the dead body, but not at

all in the living.

His descriptions of the vertebr, with all theirprocesses and ligaments, as well as his account ofthe general characters of the internal viscera,would not have been as free from error as they

are if he had derived all his knowledge from the


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dissection of the inferior animals. Moreover, it isindisputable that, within less than a hundred

years from the death of Hippocrates, the humanbody was openly dissected in the schools ofAlexandrianay, further, that even thevivisection of condemned criminals was notuncommon. It would be unreasonable to supposethat such a practice as the former sprang upsuddenly under the Ptolemies, and it seems,therefore, highly probable that it was known andtolerated in the time of Hippocrates. It is notsurprising, when we remember the rudeappliances and methods which then obtained,that in his knowledge of minute anatomyHippocrates should compare unfavourably withanatomists of the present day. Of histology, andsuch other subjects as could not be broughtwithin his direct personal observation, theknowledge of Hippocrates was necessarilydefective. Thus he wrote of the tissues withoutdistinguishing them; confusing arteries, veins,

and nerves, and speaking of muscles vaguely asflesh. But with matters within the reach of theAncient Physicians own careful observation, thecase is very different. This is well shown in hiswonderful chapter on the club-foot, in which henot only states correctly the true nature of the

malformation, but gives some very sensible


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directions for rectifying the deformity in earlylife.

When human strength was not sufficient torestore a displaced limb, he skilfully availedhimself of all the mechanical powers which werethen known. He does not appear to have beenacquainted with the use of pulleys for thepurpose, but the axles which he describes asbeing attached to the bench which bears hisname (Scamnum Hippocratis) must have beenquite capable of exercising the force required.

The work called The Aphorisms, which wasprobably written in the old age of Hippocrates,consists of more than four hundred short pithysentences, setting forth the principles ofmedicine, physiology, and natural philosophy. Alarge number of these sentences are evidentlytaken from the authors other works, especiallythose On Air, etc., On Prognostics, and On

the Articulations. They embody the result of avast amount of observation and reflection, andthe majority of them have been confirmed by theexperience of two thousand years. A proof of thehigh esteem in which they have always been heldis furnished by the fact that they have been

translated into all the languages of the civilized


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world; among others, into Hebrew, Arabic, Latin,English, Dutch, Italian, German, and French. The

following are a few examples of these aphorisms:Spontaneous lassitude indicates disease.

Old people on the whole have fewer complaintsthan the young; but those chronic diseases whichdo befall them generally never leave them.Persons who have sudden and violent attacks offainting without any obvious cause die suddenly.Of the constitutions of the year, the dry upon thewhole are more healthy than the rainy, andattended with less mortality.Phthisis most commonly occurs between theages of eighteen and thirty-five years.If one give to a person in fever the same foodwhich is given to a person in good health, what isstrength to the one is disease to the other.

Such food as is most grateful, though not sowholesome, is to be preferred to that which isbetter, but distasteful.

Life is short and the art long; the opportunityfleeting; experience fallacious and judgmentdifficult. The physician must not only do his dutyhimself, but must also make the patient, theattendants and the externals, co-operate.


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Hippocrates appears to have travelled a greatdeal, and to have practised his art in many places

far distant from his native island. A fewtraditions of what he did during his long liferemain, but differences of opinion exist as to thetruth of these stories.

Thus one story says that when Perdiccas, theKing of Macedonia, was supposed to be dying ofconsumption, Hippocrates discovered thedisorder to be love-sickness, and speedilyeffected a cure. The details of this story scarcelyseem to be worthy of credence, more especially assimilar legends have been told of entirelydifferent persons belonging to widely differenttimes. There are, however, some reasons forbelieving that Hippocrates visited theMacedonian court in the exercise of hisprofessional duties, for he mentions in the courseof his writings, among places which he hadvisited, several which were situated in

Macedonia; and, further, his son Thessalusappears to have afterwards been court physicianto Archelaus, King of Macedonia.

Another story connects the name of Hippocrateswith the Great Plague which occurred at Athens

in the time of the Peloponnesian war. It is said


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that Hippocrates advised the lighting of greatfires with wood of some aromatic kind, probably

some species of pine. These, being kindled allabout the city, stayed the progress of thepestilence. Others besides Hippocrates are,however, famous for having successfully adoptedthis practice.

A third legend states that the King of Persia,pursuing the plan (which in the two celebratedinstances of Themistocles and Pausanias hadproved successful) of attracting to his side themost distinguished persons in Greece, wrote toHippocrates asking him to pay a visit to his court,and that Hippocrates refused to go. Although thestory is discarded by many scholars, it is worthyof note that Ctesias, a kinsman andcontemporary of Hippocrates, is mentioned byXenophon in the Anabasis as being in theservice of the King of Persia. And, with regard tothe refusal of the venerable physician to comply

with the kings request, one cannot lose sight ofthe fact that such refusal was the only courseconsistent with the opinions he professed of amonarchical form of government.

After his various travels Hippocrates, as seems to

be pretty generally admitted, spent the latter


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portion of his life in Thessaly, and died at Larissaat a very advanced age.

It is difficult to speak of the skill and painstakingperseverance of Hippocrates in terms which shallnot appear exaggerated and extravagant. Hismethod of cultivating medicine was in the truespirit of the inductive philosophy. Hisdescriptions were all derived from carefulobservation of its phenomena, and, as a result,the greater number of his deductions have stoodunscathed the test of twenty centuries.

Still more difficult is it to speak with moderationof the candour which impelled Hippocrates toconfess errors into which in his earlier practicehe had fallen; or of that freedom fromsuperstition which entitled him to be spoken ofas a man who knew not how to deceive or bedeceived (qui tam fallere quam falli nescit); or,lastly, of that purity of character and true nobility

of soul which are brought so distinctly to light inthe words of the oath translated below:

I swear by Apollo the Physician and sculapius,and I call Hygeia and Panacea and all the godsand goddesses to witness, that to the best of mypower and judgment I will keep this oath and this

contract; to witto hold him, who taught me this


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Art, equally dear to me as my parents; to sharemy substance with him; to supply him if he is in

need of the necessaries of life; to regard hisoffspring in the same light as my own brothers,and to teach them this Art, if they shall desire tolearn it, without fee or contract; to impart theprecepts, the oral teaching, and all the rest of theinstruction to my own sons, and to the sons of myteacher, and to pupils who have been bound tome by contract, and who have been swornaccording to the law of medicine.

I will adopt that system of regimen which,according to my ability and judgment, I considerfor the benefit of my patients, and will protectthem from everything noxious and injurious. Iwill give no deadly medicine to any one, even ifasked, nor will I give any such counsel, andsimilarly I will not give to a woman the means ofprocuring an abortion. With purity and withholiness I will pass my life and practise my art....

Into whatever houses I enter I will go into themfor the benefit of the sick, keeping myself alooffrom every voluntary act of injustice andcorruption and lust. Whatever in the course ofmy professional practice, or outside of it, I see orhear which ought not to be spread abroad, I will

not divulge, as reckoning that all such should be


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kept secret. If I continue to observe this oath andto keep it inviolate, may it be mine to enjoy life

and the practice of the Art respected among allmen for ever. But should I violate this oath andforswear myself, may the reverse be my lot.

1 Grotes Aristotle, vol. i. p. 3.

2 Grotes History of Greece, vol. i. p. 358.


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Aristotle

About the time that Hippocrates died,Aristotle, who may be regarded as thefounder of the science of Natural History,was born (B.C. 384) in Stagira, an

unimportant Hellenic colony in Thrace, nearthe Macedonian frontier. His father was adistinguished physician, and, likeHippocrates, boasted descent from theAsclepiad. The importance attached by theAsclepiads to the habit of physical

observation, which has been already referredto in the life of Hippocrates, secured forAristotle, from his earliest years, thatfamiliarity with biological studies which is soclearly evident in many of his works.

Both parents of Aristotle died whentheir son was still a youth, and inconsequence of this he went to reside withProxenus, a native of Atarneus, who hadsettled at Stagira. Subsequently he went toAthens and joined the school of Plato. Here

he remained for about twenty years, and


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applied himself to study with such energythat he became pre-eminent even in that

distinguished band of philosophers. He issaid to have been spoken of by Plato as theintellect of the school, and to have beencompared by him to a spirited colt thatrequired the application of the rein torestrain its ardour.

Aristotle probably wrote at this timesome philosophical works, the fame of whichreached the ears of Philip, King of Macedonia,and added to the reputation which the youngphilosopher had already made with thatmonarch; for Philip is said to have written tohim on the occasion of Alexanders birth, B.C.356: King Philip of Macedonia to Aristotle,greeting. Know that a son has been born tome. I thank the gods not so much that theyhave given him to me, as that they havepermitted him to be born in the time of

Aristotle. I hope that thou wilt form him to bea king worthy to succeed me and to rule theMacedonians.

After the death of Plato, which occurredin 347 B.C., Aristotle quitted Athens and went

to Atarneus, where he stayed with Hermias,


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who was then despot of that town. Hermiaswas a remarkable man, who, from being a

slave, had contrived to raise himself to thesupreme power. He had been at Athens andhad heard Platos lectures, and had thereformed a friendship for Aristotle. With thisman the philosopher remained for threeyears, and was then compelled suddenly toseek refuge in Mitylene, owing to theperfidious murder of Hermias. The latter wasdecoyed out of the town by the Persiangeneral, seized and sent prisoner toArtaxerxes, by whom he was hanged as arebel. On leaving Atarneus, Aristotle tookwith him a niece of Hermias, named Pythias,whom he afterwards married. She diedyoung, leaving an infant daughter.

Two or three years after this, Aristotlebecame tutor to Alexander, who was thenabout thirteen years old. The philosopher

seems to have been a favourite with both theking and the prince, and, in gratitude for hisservices, Philip rebuilt Stagira and restored itto its former inhabitants, who had eitherbeen dispersed or carried into slavery. Theking is said also to have established there a

school for Aristotle. The high respect in


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which Alexander held his teacher isexpressed in his saying that he honoured him

no less than his own father, for while to onehe owed life, to the other he owed all thatmade life valuable.

In 336 B.C. Alexander, who was thenonly about twenty years of age, became king,and Aristotle soon afterwards quittedMacedonia and took up his residence inAthens once more, after an absence of abouttwelve years. Here he opened a school in theLycum, a gymnasium on the eastern side ofthe city, and continued his work there forabout twelve years, during which timeAlexander was making his brilliantconquests. The lectures were given for themost part while walking in the garden, and inconsequence, perhaps, of this, the sectreceived the name of the Peripatetics. Thediscourses were of two kindsthe esoteric, or

abstruse, and the exoteric, or familiar; theformer being delivered to the more advancedpupils only. During the greater part of thistime Aristotle kept up correspondence withAlexander, who is said3 to have placed at hisdisposal thousands of men, who were busily

employed in collecting objects and in making


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observations for the completion of thephilosophers zoological researches.

Alexander is, moreover, said to have giventhe philosopher eight hundred talents for thesame purpose.

In spite of these marks of friendship andrespect, Alexander, who was fast becomingintoxicated with success, and corrupted byAsiatic influences, gradually cooled in hisattachment towards Aristotle. This may havebeen hastened by several causes, and amongothers by the freedom of speech andrepublican opinions of Callisthenes, akinsman and disciple of Aristotle, who hadbeen, by the latters influence, appointed toattend on Alexander. Callisthenes proved sounpopular, that the king seems to haveavailed himself readily of the first plausiblepretext for putting him to death, and to havethreatened his former friend and teacher

with a similar punishment. The latter, for hispart, probably had a deep feeling ofresentment towards the destroyer of hiskinsman.

Meanwhile the Athenians knew nothing

of these altered relations between Aristotle


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and Alexander, but continued to regard thephilosopher as thoroughly imbued with

kingly notions (in spite of his writings beingquite to the contrary); so that he was anobject of suspicion and dislike to theAthenian patriots. Nevertheless, as long asAlexander was alive, Aristotle was safe frommolestation. As soon, however, asAlexanders death became known, the anti-Macedonian feeling of the Athenians burstforth, and found a victim in the philosopher.A charge of impiety was brought against him.It was alleged that he had paid divinehonours to his wife Pythias and to his friendHermias. Now, for the latter, a eunuch, whofrom the rank of a slave had raised himself tothe position of despot over a free Greciancommunity, so far from coupling his name(as Aristotle had done in his hymn) with thegreatest personages of Hellenic mythology,the Athenian public felt that no contempt was

too bitter. To escape the storm thephilosopher retired to Chalcis, in Eub a, then under garrison by Antipater, theGovernor of Macedonia, remarking in aletter, written afterwards, that he did so inorder that the Athenians might not have the

opportunity of sinning a second time against


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philosophy (the allusion being, of course, tothe fate of Socrates).

He probably intended to return toAthens again so soon as the political troubleshad abated, but in September, 322 B.C., hedied at Chalcis. An overwrought mind,coupled with indigestion and weakness of thestomach, from which he had long suffered,was most probably the cause of death. Someof his detractors, however, have asserted thathe took poison, and others that he drownedhimself in the Eub an Euripus.

It is not easy to arrive at a just estimateof the character of Aristotle. By some of hissuccessors he has been reproached withingratitude to his teacher, Plato; with servilityto Macedonian power, and with love of costlydisplay. How far these two last charges aredue to personal slander it is impossible to

say. The only ground for the first charge is,that he criticised adversely some of Platosdoctrines.

The manuscripts of Aristotles workspassed through many vicissitudes. At the

death of the philosopher they were


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bequeathed to Theophrastus, who continuedchief of the Peripatetic school for thirty-five

years. Theophrastus left them, with his ownworks, to a philosophical friend and pupil,Neleus, who conveyed them from Athens tohis residence at Scepsis, in Asia Minor. Aboutthirty or forty years after the death ofTheophrastus, the kings of Pergamus, towhom the city of Scepsis belonged, begancollecting books to form a library on theAlexandrian plan. This led the heirs of Neleusto conceal their literary treasures in a cellar,and there the manuscripts remained fornearly a century and a half, exposed to injuryfrom damp and worms. At length they weresold to Apellicon, a resident at Athens, whowas attached to the Peripatetic sect. Many ofthe manuscripts were imperfect, havingbecome worm-eaten or illegible. Thesedefects Apellicon attempted to remedy; but,being a lover of books rather than a

philosopher, he performed the worksomewhat unskilfully. When Athens wastaken by Sylla, 86 B.C., the library ofApellicon was transported to Rome. Therevarious literary Greeks obtained access to it;and, among others, Tyrannion, a grammarian

and friend of Cicero, did good service in the


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work of correction. Andronicus of Rhodesafterwards arranged the whole into sections,

and published the manuscripts with atabulated list.

The three principal works on biologywhich are extant are: The History ofAnimals; On the Parts of Animals; On theGeneration of Animals. The other biologicalworks are: On the Motion of Animals; OnRespiration; Parva Naturalia;"a series ofessays which are planned to form an entirework on sense and the sensible.

The History of Animals is the largestand most important of Aristotles works onbiology. It contains a vast amount ofinformation, not very methodically arranged,and spoiled by the occurrence here and thereof very gross errors. It consists of nine books.

The first book opens with a division ofthe body into similar and dissimilar parts.Besides thus differing in their parts, animalsalso differ in their mode of life, their actionsand dispositions. Thus some are aquatic,others terrestrial; of the former, some

breathe water, others air, and some neither.


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Of aquatic animals, some inhabit the sea, andothers rivers, lakes, or marshes. Again, some

animals are locomotive, and others arestationary. Some follow a leader, others actindependently. Various differences are in thisway pointed out, and there is no lack ofillustration and detail, but a suspicion isexcited that the generalizations aresometimes based upon insufficient facts. Thebook closes with a description of the differentparts of the human body, both internal andexternal. In speaking of the ear, Aristotleseems to have been aware of what we nowcall the Eustachian tube, for he says, There isno passage from the ear into the brain, butthere is to the roof of the mouth.4

In the second book he passes on todescribe the organs of animals. The animalsare dealt with in groupsviviparous andoviparous quadrupeds, fish, serpents, birds,

etc. The ape, elephant, chameleon, and someothers are especially noticed.

The third book continues thedescription of the internal organs. Referenceswhich are made to a diagram by letters, a, b,

c, d, show that the work was originally


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illustrated. At the close of this book Aristotlehas some remarks on milk, and mentions the

occasional appearance of milk in maleanimals. He speaks of a male goat at Lemnoswhich yielded so much that cakes of cheesewere made from it. Similar instances of thisphenomenon have been recorded byHumboldt, Burdach, Geoffroy St. Hilaire, andothers.

In the first four chapters of the fourthbook the anatomy of the invertebrata is dealtwith, and the accounts given of certainmollusca and crustacea are very careful andminute. The rest of the book is devoted to adescription of the organs of sense and voice;of sleep, and the distinctions of sex. Theaccurate knowledge which Aristotle exhibitsof the anatomy and habits of marine animals,such as the Cephalopoda and the largerCrustacea, leaves no doubt that he derived it

from actual observation. Professor Owensays, Respecting the living habits of theCephalopoda, Aristotle is more rich in detailthan any other zoological author. What isnow spoken of as the hectocotylization of oneor more of the arms of the male cephalopod

did not escape Aristotles eye. And while he


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speaks of the teeth and that which servesthese animals for a tongue, it is plain from

the context that he means in the one case thetwo halves of the parrot-like beak, and in theother the anterior end of the odontophore.

Books five to seven deal with the subjectof generation.

The eighth book contains a variety ofdetails respecting animals, their food,migrations, hibernation, and diseases; withthe influence of climate and locality uponthem.

The ninth book describes the habits andinstincts of animals. The details areinteresting; but there is, as usual, very littleattempt at classification. Disjointedstatements and sudden digressions occur, thesubjects being treated in the order in which

they presented themselves to the author.Such curious statements as the following aremet with: The raven is an enemy to the bulland the ass, for it flies round them and strikestheir eyes. If a person takes a goat by thebeard, all the rest of the herd stand by, as if

infatuated, and look at it. Female stags are


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captured by the sound of the pipe and bysinging. When two persons go out to capture

them, one shows himself, and either playsupon a pipe or sings, and the other strikesbehind, when the first gives him the signal.Swans have the power of song, especiallywhen near the end of their life; for they thenfly out to sea, and some persons sailing nearthe coast of Libya have met many of them inthe sea singing a mournful song, and haveafterwards seen some of them die. Of allwild animals, the elephant is the most tameand gentle; for many of them are capable ofinstruction and intelligence, and they havebeen taught to worship the king.

In the work On the Parts of Animals,the author considers not only the phenomenaof life exhibited by each species, but also thecause or causes to which these phenomenaare attributable. After a general introduction,

he proceeds to enumerate the three degreesof composition, viz.:(1) Composition out of what some call theelements, such as air, earth, water, and fire,or out of the elementary forces, hot and cold,solid and fluid, which form the material of all

compound substances.


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(2) Composition out of these primarysubstances of the homogeneous parts of

animals, e.g. blood, fat, marrow, brain, flesh,and bone.(3) Composition into the heterogeneous partsor organs. These parts he describes in detail,considering those belonging to sanguineousanimals first and most fully.

These divisions correspond roughly tothe threefold study of structure which wenowadays recognize as chemical, histological,and anatomical.

As examples of Aristotles method oftreatment, his descriptions of blood, thebrain, the heart, and the lung may beconsidered.

Of the blood he says, What are calledfibres are found in the blood of someanimals, but not of all. There are none, forinstance, in the blood of deer and of roes, and

for this reason the blood of such animals asthese never coagulates.... Too great an excessof water makes animals timorous.... Suchanimals, on the other hand, as have thick andabundant fibres in their blood are of a morecholeric temperament, and liable to bursts of

passion.... Bulls and boars are choleric, for


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their blood is exceedingly rich in fibres, andthe bulls, at any rate, coagulates more

rapidly than that of any other animal.... Ifthese fibres are taken out of the blood, thefluid that remains will no longer coagulate.

From these quotations it will be notedthat Aristotle attributed the coagulum to thepresence of fibres, and in this he anticipatedMalpighis discovery made in the seventeenthcentury. His remarks on the proportion ofcoagulum and serum in different animals,which is enlarged upon in the History ofAnimals,5 harmonize with modernobservations. In another of his works6 heremarks that the blood in certain diseasedconditions will not coagulate. This is knownto be the case in cholera, certain fevers,asphyxia, etc.; and the fact was probablyobtained from Hippocrates. AlthoughAristotle speaks here of entire absence of

coagulation in the blood of the deer and theroe, in the History of Animals he admits animperfect coagulation, for he says, so thattheir blood does not coagulate like that ofother animals. The animals named arecommonly hunted, and it was probably after

they had been hunted to death that he
http://ebooks.adelaide.edu.au/s/science/fathers-of-biology/chapter2.html#fn5http://ebooks.adelaide.edu.au/s/science/fathers-of-biology/chapter2.html#fn6http://ebooks.adelaide.edu.au/s/science/fathers-of-biology/chapter2.html#fn5http://ebooks.adelaide.edu.au/s/science/fathers-of-biology/chapter2.html#fn6


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examined them. Now, it is generally admittedthat coagulation under such circumstances is

imperfect and even uncommon. Thestatement as to the richness in fibres of theblood of bulls and boars has been confirmedby some modern investigations, which haveshown that the clot bears a proportion to thestrength and ferocity of the animal. Theremarks, however, as to the relative rapidityof coagulation would appear to becontradicted by later observations, forThackrah came to the conclusion thatcoagulation commenced sooner in small andweak animals than in strong.

Of the brain Aristotle makes thefollowing among other assertions: Of allparts of the body there is none so cold as thebrain.... Of all the fluids of the body it is theone that has the least blood, for, in fact, it hasno blood at all in its proper substance.... That

it has no continuity with the organs of senseis plain from simple inspection, and stillmore closely shown by the fact that when it istouched no sensation is produced.... Thebrain tempers the heat and seething of theheart.... In order that it may not itself be

absolutely without heat, blood-vessels from


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the aorta end in the membrane whichsurrounds the brain.... Of all animals man

has the largest brain in proportion to his size:and it is larger in men than in women. This isbecause the region of the heart and of thelung is hotter and richer in blood in manthan in any other animal; and in men than inwomen. This again explains why man aloneof animals stands erect. For the heat,overcoming any opposite inclination, makesgrowth take its own line of direction, which isfrom the centre of the body upwards.... Managain has more sutures in his skull than anyother animal, and the male more than thefemale. The explanation is to be found in thegreater size of the brain, which demands freeventilation proportionate to its bulk.... Thereis no brain in the hinder part of the head....The brain in all animals that have one isplaced in the front part of the head ... becausethe heart, from which sensation proceeds, is

in the front part of the body.

Although it would perhaps be difficultto find anywhere as many errors in as fewwords, yet it should be observed thatAristotle here shows himself to have been

aware of the existence of the membranes of


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the brainthe pia mater and the dura mater;and elsewhere7 he says more explicitly, Two

membranes enclose the brain; that about theskull is the stronger; the inner membrane isslighter than the outer one. And further, itshould be noted that he describes the lattermembrane as a vascular one. The fact of thebrain substance being insensible tomechanical irritation was known to Aristotle,and may have been learnt from the practiceof Hippocrates. Lastly, it should beremembered thatthough this may havebeen but a lucky guess on Aristotles partthe relative weight of brain to the entire bodyhas been shown, with few exceptions, to begreater in man than in any other animal.

In describing the heart Aristotle says:The heart lies about the centre of the body,but rather in its upper than in its lower half,and also more in front than behind.... In man

it inclines a little towards the left, so that itmay counterbalance the chilliness of thatside. It is hollow, to serve for the reception ofthe blood; while its wall is thick, that it mayserve to protect the source of heat. For here,and here alone, in all the viscera, and in fact

in all the body, there is blood without blood-


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vessels, the blood elsewhere being alwayscontained within vessels. The heart is the

first of all the parts of the body to be formed,and no sooner is it formed than it containsblood.... For no sooner is the embryo formedthan its heart is seen in motion like a livingcreature, and this before any of the otherparts. The heart is abundantly supplied withsinews.... In no animal does the heart containa bone, certainly in none of those that weourselves have inspected, with the exceptionof the horse and a certain kind of ox. Inanimals of great size the heart has threecavities; in smaller animals it has two; and inall it has at least one.

It will be observed that here Aristotle socorrectly describes the position of the humanheart as to render it probable that he isspeaking from actual inspection; althoughman is not the only animal in which the heart

is turned towards the left. In contrasting theheart with the other viscera he appears tohave overlooked the existence of thecoronary vessels, and to have imagined thatthe nutrition of the heart was effecteddirectly by the blood in its cavities. Although

the heart is not really the first part to appear,


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the observation of its very early appearancein the embryo, which he treats more fully

elsewhere,8 is alone enough to establish hisreputation as an original observer. It isremarkable that Aristotle should haveoverlooked the presence of the valves of theheart, the structure and functions of whichwere fully investigated within thirty years ofhis death by the anatomists of theAlexandrian school. This is the moreremarkable, as he calls attention here, and inthe History of Animals, to the sinews ortendons ( ) with which, he says, the heart is supplied, and by which he probably meantchiefly the chord tendine. The bone inthe heart of which he speaks was probablythe cruciform ossification which is normallyfound in the ox and the stag below the originof the aorta. It is found in the horse only inadvanced age, or under abnormal conditions.The statement that the heart contains no

more than three chambers has always beenconsidered as a very gross blunder on thepart of Aristotle. Even Cuvier, who generallylavishes upon the philosopher the mostextravagant praise, sneers at this. ProfessorHuxley,9 however, has shown, by a

comparison of several passages from the


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History of Animals, that what we now callthe right auricle was regarded by the author

as a venous sinus, as being a part not of theheart, but of the great vein (i.e. the superiorand the inferiorven cav).

Aristotle speaks of the lung as a singleorgan, sub-divided, but having a commonoutletthe trachea. Elsewhere10 he says,Canals from the heart pass to the lung anddivide in the same fashion as the windpipedoes, closely accompanying those from thewindpipe through the whole lung. Histheory of respiration, as explained in histreatise on the subject, is that it tempers theexcessive heat produced in the heart. Thelung is compared to a pair of bellows. Whenthe lung is expanded, air rushes in; when it iscontracted, the air is expelled. The heat fromthe heart causes the lung to expandcold airrushes in, the heat is reduced, the lung

collapses, and the air is expelled. The cold airdrawn into the lung reaches the bronchialtubes, and as the vessels containing hot bloodrun alongside these tubes, the air cools it andcarries off its superfluous heat. Some of theair which enters the lung gets from the

bronchial tubes into the blood-vessels by


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transudation, for there is no directcommunication between them; and this air,

penetrating the body, rapidly cools the bloodthroughout the vessels. But Aristotle did notconsider the pneuma, which thus reachedthe interior of the blood-vessels, to be exactlythe same thing as airit was a subtilizedand condensed air.11 And this we now knowto be oxygen.

The treatise On the Generation ofAnimals is an extraordinary production. Noancient and few modern works equal it incomprehensiveness of detail and profoundspeculative insight. We here find some of theobscurest problems of biology treated with amastery which, when we consider thecondition of science at that day, is trulyastounding. That there are many errors,many deficiencies, and not a littlecarelessness in the admission of facts, may be

readily imagined; nevertheless at times thework is frequently on a level with, andoccasionally even rises above, thespeculations of many advancedembryologists.12


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It commences with the statement thatthe present work is a sequel to that On the

Parts of Animals; and first the masculineand feminineprinciples are defined. Themasculine principle is the origin of all motionand generation; the feminine principle is theorigin of the material generated. Aristotlesphilosophy of nature was teleological, andthe imperfect character of his anatomicalknowledge often gives him occasion toexplain particular phenomena by finalcauses. Thus animals producing soft-shelledeggs (e.g. cartilaginous fish and vipers) aresaid to do so because they have so littlewarmth that the external surface of the eggcannot be dried.

Among insects, some (e.g. grasshopper,cricket, ant, etc.) produce young in theordinary way, by the union of the sexes; inother cases (e.g.flies and fleas) this union of

the sexes results in the production of askolex; while others have no parents, nor dothey have congresssuch are the ephemera,tipula, and the like. Aristotle discusses andrejects the theory that the male reproductiveelement is derived from every part of the

body. He concludes that instead of saying


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that it comes from all parts of the body, weshould say that it goes to them. It is not the

nutrient fluid, but that which is left over,which is secreted. Hence the larger animalshave fewer young than the smaller, for bythem the consumption of nutrient materialwill be larger and the secretion less. Anotherpoint to be noticed is, that the nutrient fluidis universally distributed through the body,but each secretion has its separate organ.... Itis thus intelligible why children resembletheir parents, since that which makes all theparts of the body, resembles that which is leftover as secretion: thus the hand, or the face,or the whole animal pre-exists in the sperm,though in an undifferentiated state( ); and what each of these is in actuality ( ), such is the sperm in potentiality ( ).

In later times the two great rival

theories put forward to account for thedevelopment of the embryo have been(a) The theory of Evolution, which makes theembryo pre-existent in the germ, and onlyrendered visible by the unfolding andexpansion of its organs.


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(b) The theory of Epigenesis, which makes theembryo arise, by a series of successive

differentiations, from a simple homogeneousmass into a complex heterogeneousorganism.

The above quotation will show howclosely Aristotle held to the theory ofEpigenesis; and in another place he says, Notat once is the animal a man or a horse, for theend is last attained; and the specific form isthe end of each development.

Spontaneous generation is nowadaysrejected by science; but Aristotle went so faras to believe that insects, molluscs, and eveneels, were spontaneously generated. It is,however, noteworthy, in view of moderninvestigations, that he looked uponputrefying matter as the source of suchdevelopment.

A chapter of this work is devoted to theconsideration of the hereditary transmissionof peculiarities from parent to offspring.

The fifth and last book contains

inquiries into the cause of variation in the


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colour of the eyes and hair, the abundance ofhair, the sleep of the embryo, sight and

hearing, voice and the teeth.

Widely different opinions have beenheld from time to time of the value ofAristotles biological labours. Thisphilosophers reputation has, perhaps,suffered most from those who have praisedhim most. The praise has often been of suchan exaggerated character as to have becomeunmeaning, and to have carried with it theimpression of insincerity on the part of thewriter. Such are the laudations of Cuvier. Tosay as he does, Alone, in fact, withoutpredecessors, without having borrowedanything from the centuries which had gonebefore, since they had produced nothingenduring, the disciple of Plato discovered anddemonstrated more truths and executedmore scientific labours in a life of sixty-two

years than twenty centuries after him wereable to do, is of course to talk nonsense, forthe method which Aristotle applied was thatwhich Hippocrates had used so well beforehim; and it is evident to any one that both hispredecessors and contemporaries are

frequently laid under contribution by


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Aristotle, although the authority is rarely, ifever, stated by him unless he is about to

refute the view put forward. Exaggeratedpraise of any author has a tendency to excitedepreciation correspondingly unjust anduntrue. It has been so in the case of this greatman. In the endeavour to depose him fromthe impossible position to which hispanegyrists had exalted him, his detractorshave gone to any length. The principalcharges brought against his biological workhave been inaccuracy and hastygeneralization. In support of the charge ofinaccuracy, some of the extraordinarystatements which are met with in his worksare adduced. These, Professor Huxley says,are not so much to be called errors asstupidities. Some, however, of theinaccuracies alleged against Aristotle arefancied rather than real. Thus he is chargedwith having represented that the arteries

contained nothing but air; that the aortaarose from the right ventricle; that the heartdid not beat in any other animal but man;that reptiles had no blood, etc.; although inreality he made no one of these assertions.There remain, nevertheless, the gross

misstatements referred to above, and which


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really do occur. Such, for instance, as thatthere is but a single bone in the neck of the

lion; that there are more teeth in male than infemale animals; that the mouth of thedolphin is placed on the under surface of thebody; that the back of the skull is empty, etc.Although these absurdities undoubtedlyoccur in Aristotles works, it by no meansfollows that he is responsible for them.Bearing in mind the curious history of themanuscripts of his treatises, we shall find itfar more reasonable to conclude that sucherrors crept in during the process ofcorrection and restoration, by menapparently ignorant of biology, than that (totake only one case) an observer who haddistinguished the cetacea from fishes and haddetected their hidden mamm, discoveredtheir lungs, and recognized the distinctcharacter of their bones, should have been soblind as to fancy that the mouth of these

animals was on the under surface of thebody.

That Aristotle made hastygeneralizations is true; but it wasunavoidable. Biology was in so early a stage

that a theory had often of necessity to be


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founded on a very slight basis of facts. Yet,notwithstanding this drawback, so great was

the sagacity of this philosopher, that many ofhis generalizations, which he himselfprobably looked upon as temporary, haveheld their ground for twenty centuries, or,having been lost sight of, have beendiscovered and put forward as original bymodern biologists. Thus the advantage ofphysiological division of labour was first setforth, says MilneEdwards, by myself in1827; and yet Aristotle had said13thatwhenever Nature is able to provide twoseparate instruments for two separate uses,without the one hampering the other, shedoes so, instead of acting like a coppersmith,who for cheapness makes a spit-and-a-candlestick in one.14 It is only when this isimpossible that she uses one organ forseveral functions.

In conclusion, we may say that the greatStagirite expounded the true principles ofscience, and that when he failed his failurewas caused by lack of materials. His desirefor completeness, perhaps, tempted him attimes to fill in gaps with such makeshifts as

came to his hand; but no one knew better


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than he did that theories must be abandonedunless their teachings tally with the

indisputable results of observation.15


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3 Pliny, Natural History, viii. c. 16.

4 History of Animals, i. 11.

5 Bk. iii. 19.

6 Meteorology, iv. 711.


8 History of Animals, vi. 3.

9 On some of the errors attributed to Aristotle.


11 See Professor Huxleys article already referred to.12 Aristotle, by G. H. Lewes, p. 325.

13 De Part. Anim., iv. 6.

14 .

15 De Gener., iii. 10, quoted by Dr. Ogle.


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Galen

Under the Ptolemies a powerful stimuluswas given to biological studies at Alexandria.Scientific knowledge was carried a step or twobeyond the limit reached by Aristotle. ThusErasistratus and Herophilus thoroughly

investigated the structure and functions of thevalves of the heart, and were the first to recognizethe nerves as organs of sensation. But,unfortunately, no complete record of theinteresting work carried on by these men hascome down to our times. The first writer after

Aristotle whose works arrest attention is CaiusPlinius Secundus, whose so-called NaturalHistory, in thirty-seven volumes, remains to thepresent day as a monument of industriouscompilation. But, as a biologist properly socalled, Pliny is absolutely without rank, for he

lacked that practical acquaintance with thesubject which alone could enable him to speakwith authority. Of information he had an almostinexhaustible store; of actual knowledge, theresult of observation and experience, so far asbiological studies were concerned, he had butlittle. This was largely due to the encyclopdic


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character of the work he undertook; his mentalpowers were weighed down by an enormous

mass of unarranged and ill-digested materials.But it was due also to the peculiar bent of Plinysmind. He was not, like Aristotle, an originalthinker; he was essentially a student of books, animmensely industrious but not always judiciouscompiler. Often his selections from other worksprove that he failed to appreciate the relativeimportance of the different subjects to which hemade reference. His knowledge of the Greeklanguage appears, too, to have been defective, forhe gives at times the wrong Latin names toobjects described by his Greek authorities. Tothese defects must be added his marvellousreadiness to believe any statement, provided onlythat it was uncommon; while, on the other hand,he showed an indefensible scepticism in regardto what was really deserving of attention. Thechief value of his work consists in the historicaland chronological notes of the progress of some

of the subjects of which he treatsfragments ofwritings which would otherwise be lost to us.Pliny was killed in the destruction of Pompeii,A.D. 79.


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Claudius Galenus was born at Pergamus, in AsiaMinor, in the hundred and thirty-first year of the

Christian era. Few writers ever exercised for solong a time such an undisputed sway over theopinions of mankind as did this wonderful man.His authority was estimated at a much higherrate than that of all the biological writerscombined who flourished during a period ofmore than twelve centuries, and it was oftenconsidered a sufficient argument against ahypothesis, or even an alleged matter of fact, thatit was contrary to Galen.

Endowed by nature with a penetrating geniusand a mind of restless energy, he was eminentlyqualified to profit by a comprehensive and liberaleducation. And such he received. His father,Nicon, an architect, was a man of learning andabilitya distinguished mathematician and anastronomerand seems to have devoted muchtime and care to the education of his son. The

youth appears to have studied philosophysuccessively in the schools of the Stoics,Academics, Peripatetics, and Epicureans, withoutattaching himself exclusively to any one of these,and to have taken from each what he thought tobe the most essential parts of their system,

rejecting, however, altogether the tenets of the


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Epicureans. At the age of twenty-one, on thedeath of his father, he went to Smyrna to

continue the study of medicine, to which he hadnow devoted himself. After leaving this place andhaving travelled extensively, he took up hisresidence at Alexandria, which was then the mostfavourable spot for the pursuit of medicalstudies. Here he is said to have remained until hewas twenty-eight years of age, when hisreputation secured his appointment, in his nativecity of Pergamus, to the office of physician incharge of the athletes in the gymnasia situatedwithin the precincts of the temple of sculapius.For five or six years he lived in Pergamus, andthen a revolt compelled him to leave his nativetown. The advantages offered by Rome led him toremove thither and take up his residence in thecapital of the world. Here his skill, sagacity, andknowledge soon brought him into notice, andexcited the jealousy of the Roman doctors, whichwas still further increased by some wonderful

cures the young Greek physician succeeded ineffecting. Possibly it was owing to the ill feelingshown to Galen that, on the outbreak of anepidemic a year afterwards, he left the imperialcity and proceeded to Brindisi, and embarked forGreece. It was his intention to devote his time to

the study of natural history, and for this purpose


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he visited Cyprus, Palestine, and Lemnos. Whileat the last-named place, however, he was

suddenly summoned to Aquileia to meet theEmperors Marcus Aurelius and Lucius Verus. Hetravelled through Thrace and Macedonia on foot,met the imperial personages, and prepared forthem a medicine, for which he seems to havebeen famous, and which is spoken of as thetheriac. It was probably some combination ofopium with various aromatics and stimulants, forantidotes of many different kinds were habituallytaken by the Romans to preserve them from theill effects of poison and of the bites of venomousanimals.16

With the Emperor M. Aurelius he returned toRome, and became afterwards doctor to theyoung Emperor Commodus. He did not,however, remain for a long period at Rome, andprobably passed the greater part of the rest of hislife in his native country.

Although the date of his death is not positivelyknown, yet it appears from a passage17 in hiswritings that he was living in the reign ofSeptimius Severus; and Suidas seems to havereason for asserting that he reached his

seventieth year.


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Galens writings represent the commondepository of the anatomical knowledge of the

day; what he had learnt from many teachers,rather than the results of his own personalresearch. Roughly speaking, they deal with thefollowing subjects: Anatomy and Physiology,Dietetics and Hygiene, Pathology, Diagnosis andSemeiology, Pharmacy and Materia Medica,Therapeutics.

The only works of this voluminous writer atwhich we can here glance are those dealing withAnatomy and Physiology. These exhibitnumerous illustrations of Galens familiarity withpractical anatomy, although it was most likelycomparative rather than human anatomy atwhich he especially worked. Indeed, he seems tohave had but few opportunities of carrying onhuman dissections, for he thinks himself happyin having been able to examine at Alexandria twohuman skeletons; and he recommends the

dissection of monkeys because of their exactresemblance to man. To this disadvantage may,perhaps, be attributed the readiness, whichsometimes appears, to assume identity oforganization between man and the brutes. Thus,because in certain animals he found a double

biliary duct, he concluded the same to be the case


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in man, and in one instance he proceeded todeduce the cause of disease from this erroneous

assumption.

He supposed that there were three modes ofexistence in man, namely(a) The nutritive, which was common to allanimals and plants, of which the liver was thesource.(b) The vital, of which the heart was the source.(c) The rational, of which the brain was thesource.Again, he considered that the animal economypossessed four natural powers(1) The attractive.(2) The alterative or assimilative.(3) The retentive or digestive.(4) The expulsive.

Like his predecessors, he asserted that there werefour humours, namely, blood, yellow bile, black

bile, and aqueous serum. He held that it was theoffice of the liver to complete the process ofsanguification commenced in the stomach, andthat during this process the yellow bile wasattracted by the branches of the hepatic duct andgall-bladder; the black bile being attracted by the

spleen, and the aqueous humour by the two


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kidneys; while the liver itself retained the pureblood, which was afterwards attracted by the

heart through the vena cava, by whoseramifications it was distributed to the variousparts of the body.

Following Aristotle especially, he regarded hair,nails, arteries, veins, cartilage, bone, ligament,membranes, glands, fat, and muscle as thesimplest constituents of the body, formedimmediately from the blood, and perfectlyhomogeneous in character. The organicmembers, e.g. lungs, liver, etc., he looked upon asformed of several of the foregoing simple parts.The osteology contained in Galens works isnearly as perfect as that of the present day. Hecorrectly names and describes the bones andsutures of the cranium; notices the quadrilateralshape of the parietals, the peculiar situation andshape of the sphenoid, and the form andcharacter of the ethmoid, malar, maxillary, and

nasal bones. He divides the vertebral columnsinto cervical, dorsal, and lumbar portions.

With regard to the nervous system, he taughtthat the nerves of the senses are distinct fromthose which impart the power of motion to

musclesthat the former are derived from the


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anterior parts of the brain, while the latter arisefrom the posterior portion, or from the spinal

cord. He maintained that the nerves of the finersenses are formed of matter too soft to be thevehicles of muscular motion; whereas, on theother hand, the nerves of motion are too hard tobe susceptible of fine sensibility. His descriptionof the method of demonstrating the differentparts of the brain by dissection is veryinteresting, and, like his references to variousinstruments and contrivances, proves him tohave been a practical and experienced anatomist.In his description of the organs and process ofnutrition, absorption by the veins of the stomachis correctly noticed, and the union of themesenteric veins into one common vena port ispointed out. The communications between theramifications of the vena port and of the properveins of the liver are supposed by Galen to beeffected by means of anastomosing pores orchannels. Although it is evident that Galen was

ignorant of the true absorbent system, yet heappears to have been aware of the lacteals; for hesays that in addition to those mesenteric veinswhich by their union form the vena port, thereare visible in every part of the mesentery otherveins, proceeding also from the intestines, which

terminate in glands; and he supposes that these


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veins are intended for the nourishment of theintestines themselves. Some of Galens

contemporaries asserted that upon exposing themesentery of a sucking animal several smallvessels were seen filled first with air, andafterwards with milk. They had, doubtless,mistaken colourless lymph for air; but Galenridicules both assertions, and thereby shows thathe had not examined the contents of the lacteals.This is somewhat remarkable, because as a rulehe omitted no opportunity of determining withcertainty, by vivisection and experiments onliving animals, the uses of the various parts of thebody. As an illustration of this, we have hiscorrect statement, established by experiment,that the pylorus acts as a valve only during theprocess of digestion, and that it is relaxed whendigestion is completed.

He recognizes that the flesh of the heart issomewhat different to that of the muscles of

voluntary motion. Its fibres are described asbeing arranged in longitudinal and transversebundles; the former by their contractionsshortening the organ, the latter compressing andnarrowing it. Such statements show that heregarded the heart as essentially muscular. He

thought, however, that it was entirely destitute of


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nerves. Although he admitted that possibly it hadone small branch derived from the nervus vagus

sent to it, yet he entirely overlooked the greatnervous plexus surrounding the roots of theblood-vessels, from which branches proceed incompany with the branches of the coronaryarteries and veins, and penetrate the muscularsubstance of the ventricles. He endeavoured toprove, by experiment, observation, andreasoning, that the arteries as well as the veinscontained blood, and in this connection he tellsan amusing story. A certain teacher of anatomy,who had declared that the aorta contained noblood, was earnestly desired by his pupils, whowere ardent disciples of Galen, to exhibit therequisite demonstration, they themselvesoffering animals for the experiment. He,however, after various subterfuges, declined,until they promised to give him a suitableremuneration, which they raised by subscriptionamong themselves to the amount of a thousand

drachm (perhaps 30). The professor, beingthus compelled to commence the experiment,totally failed in his attempt to cut down upon theaorta, to the no small amusement of his pupils,who, thereupon taking up the experimentthemselves, made an opening into the thorax in

the way in which they had been instructed by


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Galen, passed one ligature round the aorta at thepart where it attaches itself to the spine, and

another at its origin, and then, by opening theintervening portion of the artery, showed thatblood was contained in it.

The arteries, Galen thought, possessed apulsative and attractive power of their own,independently of the heart, the moment of theirdilatation being the moment of their activity.They, in fact, drew their charge from the heart, asthe heart by its diastole drew its charge from thevena cava and the pulmonary vein. The pulse ofthe arteries, he also thought, was propagated bytheir coats, not by the wave of blood thrown intothem by the heart. He taught that at every systoleof the arteries a certain portion of their contentswas discharged at their extremities, namely, bythe exhalents and secretory vessels. Though hedemonstrated the anastomosis of arteries andveins, he nowhere hints his belief that the

contents of the former pass into the latter, to beconveyed back to the heart, and from it to beagain diffused over the body. He made a nearapproach to the Harveian theory of thecirculation, as Harvey himself admits in his DeMotu Cordis;"18 but the grand point of difference

between Galen and Harvey is the question


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whether or not, at every systole of the leftventricle, more blood is thrown out than is

expended on exhalation, secretion, and nutrition.Upon this point Galen held the negative, andHarvey, as we all know, the affirmative.

The famous Asclepiads held that respiration wasfor the generation of the soul itself, breath andlife being thus considered to be identical.Hippocrates thought it was for the nutrition andrefrigeration of the innate heat, Aristotle for itsventilation, Erasistratus for the filling of thearteries with spirits. All these opinions arediscussed and commented upon by Galen, whodetermines the purposes of respiration to be (1)to preserve the animal heat; (2) to evacuate fromthe blood the products of combustion.

He conjectured that there was in atmospheric airnot only a quality friendly to the vital spirit, butalso a quality inimical to it, which conjecture he

drew from observation of the various phenomenaaccompanying the support and the extinction offlame; and he says that if we could find out whyflame is extinguished by absence of the air, wemight then know the nature of that substancewhich imparts warmth to the blood during the

process of respiration.


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On another occasion he says that it is evidently

the quality and not thequantity of the air which isnecessary to life. He further shows that herecognized the analogy between respiration andcombustion, by comparing the lungs to a lamp,the heart to its wick, the blood to the oil, and theanimal heat to the flame.

From certain observations in various parts of hisworks, it appears that, although ignorant of thedoctrine of atmospheric pressure, he wasacquainted with some of its practical effects.Thus, he says, if you put one end of an open tubeunder water and suck out the air with the otherend, you will draw up water into the mouth, andthat it is in this way that infants extract the milkfrom the mothers breast.

Again, Erasistratus supposed that the vapour ofcharcoal and of certain pits and wells was fatal to

life because lighter than common air, but Galenmaintained it to be heavier.

He describes two kinds of respiration, one by themouths of the arteries of the lungs, and one bythe mouths of the arteries of the skin. In each

case, he says, the surrounding air is drawn into


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the vessels during their diastole, for the purposeof cooling the blood, and during their systole the

fuliginous particles derived from the blood andother fluids of the body are forced out.

He considers the diaphragm to be the principalmuscle of respiration, but he makes a cleardistinction between ordinary respiration, whichhe calls a natural and involuntary effort, and thatdeliberate and forced respiration which isobedient to the will; and he says that there aredifferent muscles for the two purposes.Elsewhere he particularly points out the two setsof intercostal muscles and their mode of action,of which, before his time, he asserts thatanatomists were ignorant.

He describes various effects produced onrespiration and on the voice by the division ofthose nerves which are connected with thethorax; and shows particularly the effect of

dividing the recurrent branch of his sixth pair ofcerebral nerves (the pneumogastric of modernanatomy). He explains how it happens that afterdivision of the spinal cord, provided that divisionbe beneath the lower termination of the neck, thediaphragm will still continue to actin

consequence, namely, of the origin of the phrenic


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nerve being above the lower termination of theneck.

Before the time of Galen the medical professionwas divided into several sects, e.g. Dogmatici,Empirici, Eclectici, Pneumatici, andEpisynthetici, who were always disputing withone another. After his time all sects seem to havemerged in his followers. The subsequent Greekand Roman biological writers were merecompilers from his works, and as soon as hiswritings were translated into Arabic they were atonce adopted throughout the East to theexclusion of all others. He remained paramountthroughout the civilized world until within thelast three hundred years. In the records of theCollege of Physicians of England we read that Dr.Geynes was cited before the college in 1559 forimpugning the infallibility of Galen, and was onlyadmitted again into the privileges of hisfellowship on acknowledgment of his error, and

humble recantation signed with his own hand.Kurt Sprengel has well said that if the physicianswho remained so faithfully attached to Galenssystem had inherited his penetrating mind, hisobserving glance, and his depth, the art ofhealing would have approached the limit of

perfection before all the other sciences; but it was


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written in the book of destiny that mind andreason were to bend under the yoke of

superstition and barbarism, and were only toemerge after centuries of lethargic sleep.

16 Hence the name .

17 De Antidotis, i. 13, vol. xiv. p. 65, Kuhn.

18 Ex ipsius etiam Galeni verbis hanc veritatem confirmari posse,scilicet: non solum posse sanguinem e vena arteriosa in arteriam

venosam et inde in sinistrum ventriculum cordis, et postea inarterias transmitti.De Motu Cordis, cap. vii.


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Vesalius

The authority of Galen, at once a despotism and areligion, was scarcely ever called in question untilthe sixteenth century. No attempt worthrecording was made during thirteen hundredyears to extend the boundary of scientific

knowledge in anatomy and physiology. It is truethat the scholastic philosopher, Albertus Magnus,who was for a short time (12601262) Bishop ofRatisbon, in the middle of the thirteenth centurywrote a History of Animals, which was aremarkable production for the age in which he

lived; although Sir Thomas Browne, in hisfamous Enquiries into Common Errors, speaksof these Tractates as requiring to be receivedwith caution, adding as regards Albertus that hewas a man who much advanced these opinions bythe authoritie of his name, and delivered most

conceits, with strickt enquirie into few.

As regards human anatomy, it was considered,during the Middle Ages, to be impiety to touchwith a scalpel the dead image of God, as mansbody was called. Mundinus, the professor of

medicine at Bologna from 1315 to 1318, was the


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first to attempt any such thing. He exhibited thepublic dissection of three bodies, but by this

created so great a scandal that he gave up thepractice, and contented himself with publishing awork, De Anatome, which formed a sort ofcommentary on Galen. This work, with additions,continued to be the text-book of the schools untilthe time of Vesalius, who founded the study ofanatomy as nowadays pursued.

Andreas Vesalius was born at Brussels, on thelast day of the year 1514, of a family which forseveral generations had been eminent formedical attainments. He was sent as a boy toLouvain, where he spent the greater part of hisleisure in researches into the mechanism of thelower animals. He was a born dissector, who,after careful examination, in his early days, ofrats, moles, dogs, cats, monkeys, and the like,came, in after-life, to be dissatisfied with any lessknowledge of the anatomy of man.

He acquired great proficiency in the scholarshipof the day. Indeed the Latin, in which heafterwards wrote his great work, is so singularlypure that one of his detractors pretended thatVesalius must have got some good scholar to

write the Latin for him. Latin was not the only


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language in which he was proficient; he addedGreek and Arabic to his other accomplishments,

and this for the purpose of reading the greatbiological works in the languages in which theywere originally written. From Louvain the youthwent to Paris, where he studied anatomy under amost distinguished physician, Sylvius. It was thepractice of that illustrious professor to read to hisclass Galen on the Use of Parts, omitting nearlyall the sections where exact knowledge ofanatomical detail was necessary. Sometimes anattempt was made to illustrate the lecture by thedissection of a dog, but such illustration moreoften exposed the professors ignorance than itadded to the students knowledge. Indirectly,however, it did good, for whenever Sylvius, afterhaving tried in vain to demonstrate some muscle,or nerve, or vein, left the room, his pupil Vesaliusslipped down to the table, dissected out the partwith great neatness, and triumphantly called theprofessors attention to it on his return.

Besides studying under Sylvius, Vesalius had forhis teacher at Paris the famous Winter, ofAndernach, who was physician to Francis I. Thislearned man, in a work published three yearsafter this period, speaks of Vesalius as a youth of

great promise. At the age of nineteen Vesalius


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returned to Louvain; and here for the first timehe openly demonstrated from the human subject.

In this connection a somewhat ghastly story istold, which serves to show the intensity of theenthusiasm with which our anatomist wasinspired. On a certain evening it chanced thatVesalius, in company with a friend, had rambledout of the gates of Louvain to a spot where thebodies of executed criminals were wont to beexposed. A noted robber had been executed. Hisbody had been chained to a stake and slowlyroasted; and the birds had so entirely strippedthe bones of every vestige of flesh, that a perfectskeleton, complete and clean, was suspendedbefore the eyes of the anatomist, who had beenstriving hitherto to piece together such a thingout of the bones of many people, gathered asoccasion offered. Mounting upon the shoulder ofhis friend, Vesalius ascended the charred stakeand forcibly tore away the limbs, leaving only thetrunk, which was securely bound by iron chains.

With these stolen bones under their clothes thetwo youths returned to Louvain. In the night,however, and alone, the sturdy Vesalius found hisway again to the placewhich to most men, atany rate in those times, would have beenassociated with unspeakable horrorsand there,

by sheer force, wrenched away the trunk, and


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buried it. Then leisurely and carefully, day afterday, he smuggled through the city gates bone

after bone. Afterwards, when he had set up theperfect skeleton in his own house, he did nothesitate to demonstrate from it. But such an actof daring plunder could not escape detection, andhe was banished from Louvain for the offence.This story is here quoted only to show theextraordinary physical and moral courage whichthe anatomist possessed; which upheld himthrough toils, dangers, and disgusts; and bywhich he was strengthened to carry on, even in acruel and superstitious age, and placed, as hewas, on the very threshold of the Inquisition, awork at all times repulsive to flesh and blood.

After serving for a short time as a surgeon in thearmy of the Emperor Charles V., Vesalius went toItaly, where he at once attracted the attention ofthe most learned men, and became, at the age oftwenty-two, Professor of Anatomy at the

University of Padua. This was the first purelyanatomical professorship that had beenestablished out of the funds of any university. Forseven years he held the office, and he was at thesame time professor at Bologna and at Pisa.During these years his lectures were always well

attended, for they were a striking innovation on


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the tameness of conventional routine. In eachuniversity the services of the professor were

confined to a short course of demonstrations, sothat his duties were complete when he had spent,during the winter, a few weeks at each of thethree towns in succession. He then returned toVenice, which he appears to have made his head-quarters. At this city, as well as at Pisa, specialfacilities were offered to the professor forobtaining bodies either of condemned criminalsor others. At Padua and Bologna the enthusiasmof the students, who became resurrectionists ontheir teachers behalf, kept the lecture-tablesupplied with specimens. They were in the habitof watching all the symptoms in men dying of afatal malady, and noting where, after death, suchmen were buried. The seclusion of the graveyardwas then invaded, and the corpse secretlyconveyed by Andreas to his chamber, andconcealed sometimes in his own bed. A diligentsearch was at once made to determine accurately

the cause of death. This pitiless zeal for correctdetails in anatomy, associated as it was withindefatigable practice in physic, appeared toVesalius, as it does to his successors of to-day, tobe the only satisfactory method of acquiring thatknowledge which is essential to a doctor. Thus it

was that he, who at the age of twenty-two was


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able to name, with his eyes blindfolded, anyhuman bone put into his hand, who was deeply

versed in comparative anatomy, and had moreaccurate knowledge of the human frame than anygraybeard of the time, enjoyed afterwards areputation as a physician which was unbounded.One illustration of his sagacity in diagnosis willsuffice. A patient of two famous court physici

fathers of biology, by charles mcrae

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