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in teaching principles, we should have the same situation as Dr.Michaelis suggests we should adopt for medical teaching. Thathis idea would improve the standard of medical teaching I donot doubt. But surely a far better way would be to adopt thesame methods as for the training of school teachers and make asatisfactory attendance at a course in the education departmenta sine qua non for an applicant for a medical teaching post.Indeed, why should this department not be invited to advise onhow best to teach the various subjects that go to make up themedical course ?

Professor Erskine and Dr. O’Morchoe would find education-ists most sympathetic towards their idea of teaching principles(or, should we rather say, of leading students to find out prin-ciples for themselves) rather than a mass of detail. As a formerteacher, this was my own method of learning while a medicalstudent, but all around me were brilliant physicians, surgeons,biochemists, bacteriologists, without a glimmer of light on thesimple principles of how to conduct themselves in front of aclass. Frequent suggestions have been made that lectures shouldbe abolished. The plain truth is that in many cases this wouldbring teaching to an end, since this method of direct telling, thelast resort of the teacher destitute of ideas, is the only methodknown to many medical teachers.

In case I may be accused of breaking my Hippocratic oathin not honouring my teachers, may I say that the excellence ofthe teaching in the departments of anatomy and physiology inthe Leeds Medical School is an example, over 20 years ago, ofthe truth of the conclusion that your contributors have nowcome to—that principles count for more than detail.

Great Glen, G. A. STANTON.Leicestershire.G. A. STANTON.

DOCTORS FOR THE FORCES

SiR,ŇIn my letter of Oct. 28 "fictitious" is a

changeling. I described objections to a combinedmedical service as factitious: though on reflection somemay have been both.The Radcliffe Infirmary, C. W. M. WHITT Y.Oxford.

*** We apologise to Dr. Whitty for introducing thismistake.-ED. L.

C. W. M. WHITTY.The Radcliffe Infirmary,

Oxford.

IMPORTED MALARIA

SIR,-Since the advent of proguanil and pyrimethaminein malaria prophylaxis, Europeans living in malariousregions have been able to live and work in hyperendemicand endemic malarious parts of the world, and, despitefrequent infections, remain free of malaria fever and

parasitsemia. Unfortunately the official advice given thatthe routine taking of prophylactic drugs should be con-tinued for at least one month after leaving a malariousarea is often neglected, judged by the number of overtcases which come to our notice.Of 60 cases of Plasmodium falciparum (malignant tertian)

infection in which I have examined blood-films, all were frompeople who had recently returned to this country, either retired,on leave, or returning from a holiday or business trip in tropicalAfrica. Their ages ranged from the pre-teens to 50, and someof them had been having severe fever for days or even weeksbefore malaria was diagnosed; and there were 4 deaths.

In one case, a boy aged 10 who had spent the summer holidaywith his parents in Nigeria stopped taking his prophylacticdrug on the day he boarded the plane for the homeward jour-ney. A fortnight later he had a severe attack of fever due toP. falciparum, and his blood-film showed a heavy parasitxmiawith developing schizonts in the peripheral circulation, which isusually a sign of a prolonged untreated infection, and this boywas no exception to the rule.

At least 12 of the 60 patients stopped drug prophylaxis eitheron the day of their departure from a malarious region, or a fewdays after arrival in the U.K. Many of the remainder probablycome into the same category.

Despite the many malaria control and eradication schemes inoperation, malaria is still rampant in huge tracts of Africa, andthe political disturbances in many parts have stopped or greatlycurtailed control work. People returning to this country shouldbe told with emphasis that drug prophylaxis must be continuedfor at least 30 days after leaving a malarious area and that, in theevent of fever after this time and up to one year, they shouldtell their general practitioner that they have recently been in amalarious area.Most of the 60 patients had flown to this country and so

could quite well have been infected the day before arrival. Airtravel makes it possible for schoolchildren to spend their

holidays with their parents in tropical Africa, as is evident if onevisits London Airport a day or two before a new school termbegins. These children should be given a month’s supply of theprophylactic drug of choice and told to give them to a teacheron returning to school. There should be written instructions tothe teacher emphasising the importance of seeing that the pupiltakes his pills regularly until they are expended and that, in theevent of fever, especially " P.u.o.", the school doctor beinformed so that a blood-film can be examined to excludemalaria. This also applies to adults returning to this country,and here it may be mentioned that blood-films may be sent tome at the address below.

Malaria Reference Laboratory, P G CrjTTTi;Horton Hospital, Epsom, Surrey... SHUTE.

1. Albright, F., Reifenstein, E. C. The Parathyroid Glands and MetabolicBone Disease; p. 13 et seq. London, 1948.

2. Hyde, R. D., Vaughan-Jones, R., McSwiney, R. R., Prunty, F. T. G.Lancet, 1960, i, 250.

3. McSwiney, R. R., Prunty, F. T. G. Proc. R. Soc. Med. 1961, 54, 639.

P. G. SHUTE.Malaria Reference Laboratory,

Horton Hospital, Epsom, Surrey.

PRIMARY HYPERPARATHYROIDISM

SiR,łYour leader of Sept. 16, in dismissing tests forphosphaturia in a few words, seems to us to be misleading.We think you would agree that tests for parathyroid

overactivity should be based on the known physiologicaleffects of the hormone. The earliest and most constant ofthese is the production of phosphaturia.1 It is possible toproduce phosphaturia without hypercalcxmia, and it isreasonable to suppose that cases of primary hyperpara-thyroidism may occur with this combination.

In addition, the differential diagnosis of hypercal-caemia is often difficult, as you emphasise. The demon-stration of phosphaturia strongly reinforces the diagnosisof primary hyperparathyroidism; its absence shoulddirect attention to the many other causes of hypercal-casmia.The question, then, is whether there is a reliable test

for phosphaturia. We would agree with your statement ifit were qualified by the italicised words:

" Tests based onthe renal excretion of phosphorus at spontaneous concen-trations of plasma-phosphorus are... unhelpful... andparticularly liable to mislead in patients with renal stones."But the measurement of the theoretical renal thresholdfor phosphorus, when the plasma-phosphorus concentra-tion is artificially increased has helped to separate ourrenal-stone patients into those with primary hyperpara-thyroidism (threshold 2-0 mg. per 100 ml. or less) andthose without (threshold 2-1 to 4-9).3 Measures of phos-phaturia at spontaneous plasma-phosphorus concentra-tions were conducted immediately before the thresholdmeasurements and gave a high proportion of false-posi-tive results, and a few false negatives. 3

In 5 cases there has been a low threshold when the serumtotal calcium and ionised calcium, measured at the same time,have been normal, which confirms by experience the expecta-tion that this situation might arise. We do not suggest that theserum-calcium is not raised in primary hyperparathyroidismbut that it can be increased and still be within normal limits,particularly in mild cases which nevertheless have phosphaturia.