490

ANNOTATIONSECLAMPSIA AND THE PITUITARY

THE intermediate lobe of the pituitary gland secretesa hormone, or a mixture of hormones, known as vaso-pressin, which exerts two very characteristic phar-macological effects-namely, vasoconstriction and

postponement of the excretion of water but not saltthrough the kidneys. The effect of lack of thishormone, or at least of its antidiuretic moiety, is seenclinically in the picture of diabetes insipidus. Yetthe clinical counterpart of excessive secretion of

vasopressin, which surely must occur, has never beendefined. If a pharmacologist were invited to speculateon the probable nature of this imaginary syndrome, hemight well predict a rise in blood pressure and a

tendency towards an accumulation in the tissues ofoedema-nuid which would be rather poor in salt. Inextreme cases he might foresee a degree of vaso-constriction intense enough to cause focal ischsemicnecrosis in various organs. Furthermore, knowingthat pituitrin combined with a high water-intakecan cause convulsions in normal animals andprecipitate fits in epileptic subjects, he might alsoanticipate convulsions. In other words, he mightpostulate a syndrome which would tally fairly closelywith the pre-eclamptic and eclamptic toxsemias of

pregnancy. It is not surprising then that the idea thatthese toxaemias are due to overactivity of the pituitary---:by no means a novel one-is attracting considerableattention at a time when new facts about that glandare coming to light almost every week, and if thehypothesis can be translated from speculation todemonstrated fact most of the mystery surroundingeclampsia will vanish.

Such direct evidence as has so far accumulated isnot entirely convincing. Prof. Harvey Cushing’s 1recent observation that the posterior lobe of the

pituitary is invaded by basophilic cells from the moreanterior parts of the gland in eclampsia is suggestive,but unfortunately he found the same change in twonormal control glands. Many attempts have also beenmade to isolate pressor substances from toxæmic

blood, but the technical difficulties are great, theresults obtained have been equivocal, and a pressoreffect is by no means peculiar to pituitary extracts.On the other hand, the antidiuretic property of

pituitrin is unique, for no other known pharmacologicalagent will suspend excretion of water while allowingfree passage of salt through the kidney. For thisreason the statement of K. J. Anselmino and F.Hoffman 2 that ultra filtrates derived from toxæmicblood cause postponement of diuresis when injectedinto rabbits is of considerable importance. Theseworkers claim to have demonstrated that togaemicblood contains a principle identical with vasopressin,in concentrations ranging from 0-002 to 0-008 unitsof pituitrin per c.cm. and depending on the severityof the clinical manifestations. F. B. Byrom andC. Wilson 3 have recently attempted to confirm theseconclusions, but without much success. Finding thatthey were unable to obtain consistent results withrabbits, they employed instead a method devised byJ. H. Burn 4 for the quantitative assay of the anti-diuretic principle, in which the rat is used as theexperimental animal; and their first step was tojustify this change in technique by demonstratingthat the rat method was sensitive enough to reveal

1 Amer. Jour. Path., 1933, ix., 539.2 Klin. Woch., 1931, x., 1438.

3 Quart. Jour. Med., 1934, iii., 361.4 Quart. Jour. Pharm. and Pharmacol., 1931, iv., 517.

the presence of pituitrin in the minimum dilutionmentioned above. They then performed 38 experi-ments with ultrafiltrates derived from blood in 13cases of toxaemia, but found evidence of vasopressinin only four instances, as compared with five instancesin a control series of 44 experiments in which normalultrafiltrate or saline was used as the test solution.Byrom and Wilson conclude that if an excess of

pituitrin is present in the blood in eclampsia itsconcentration is considerably lower than Anselminoand Hoffman suggest. This does not necessarilyimply that the pituitary hypothesis of eclampsia isuntenable, but it suggests that further evidence is

urgently needed before the hypothesis can be acceptedas proven.

APTITUDE TESTS FOR MEDICAL STUDENTS

FOR some years a Committee of the Associationof American Medical Colleges has been experimentingwith tests for picking out those applicants whohave the ability to complete successfully the medicalschool course. The form of the test as at presentused includes seven parts : (1) comprehension andretention; (2) visual memory; (3) memory for content;(4) logical reasoning ; (5) scientific vocabulary;(6) ability to follow directions; and (7) understandingof printed material. During the past year it was

applied to as many as 9000 students. A detailed studyof the results of this work has been made, and waspresented by the secretary to the committee, Dr. F. A.Moss, at the forty-fourth annual meeting of theAssociation held in Rochester and Minneapolisin 1933.1 A considerable degree of correlationis shown between success in the aptitude test andsuccess in the medical schools. For instance, inthe school-year 1929-30 the test was given to some5000 freshmen medical students. Of the 10 percent. who made the highest scores in the test noman failed to graduate and their average medicalschool grade was 86-0 for the four years’ course.

Of the 10 per cent. who made the lowest scores in thetest, 54 per cent. failed to graduate (40 per cent.failed in the first year), and their average grade forthe four years was only 714. On the other hand,these tests resemble those developed by industrialpsychologists for detecting the accident-prone, inthat while they are successful in broadly separatingthe sheep from the goats they cannot be confidentlyrelied upon to place every individual in the rightcategory. The correlation between success in thetest and success in the medical school is certainlynot absolute, or anything approaching the absolute.The more serious discrepancies-students who scorehighly in the test and do poor medical school work,and students who fail at the tests but succeed in theschools-have been specially examined by Dr. Moss.By a questionnaire addressed to the deans of variousmedical schools he sought to discover whetherpersonal factors were the responsible agents. Thechief reasons advanced for the unexpected failureswere ill-health, financial worries, too little study, ortoo many outside interests. Even the best aptitudetests must "gang aft agley " when the would-bephysician is "a ’play boy’ with many love affairs,"or is unable to resist the " social distraction " of theathletic team ; while "incompatibility with certainprofessors " was too much of a handicap to one.

The unexpected successes, on the other hand (those

1 Published in the Journal of the Assoc. of Amer. Med. Colleges,March, 1934.