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experience of a number of contributing sciences shouldbe part of the pharmacologist’s education. Can all thisbe satisfactorily included in the three years’ work

typical of most first degrees ? Or would it be wiser toexplore further the idea of a common human biologicalscience first-degree course with specialisation in pharma-cology, among other options, deferred to the final year orto a postgraduate M.sc. year ? As an alternative, M.sc.courses in pharmacology could be offered to those withfirst degrees in appropriate subjects. Such possibilities,and the extent to which they may justifiably be providedto meet the national need for pharmacologists, should beinvestigated. Postgraduate study in pharmacologydepartments has increased greatly. Compared with 78and 132 in 1952 and 1957, there were 236 postgraduatesin 1962. These figures, and the number of under-graduates to whom some teaching in pharmacology isalready given (3728 in 1962), support PATON’s conclu-sion that the " supply could readily be increased if postswere both attractive and known to be ".

In some general ways, the results of the British survey

I agree with those of an analysis 3 of the growth of

, graduate education in pharmacology in the UnitedStates. There too the number of graduates and post-doctoral trainees in pharmacology has increased sub-stantially, " but there is no positive evidence that thedemand for pharmacologists has been satisfied ".

Special training grants to medical schools from theNational Institutes of Health have enabled theseschools to enlarge their staff engaged in postgraduatetraining to a greater extent and more rapidly than schoolswhich did not receive grants. Although output of post-graduates with an M.sc. or PH.D. has increased, thenumber of PH.D. degrees awarded per 100 staff engagedin their teaching has shown a small decrease. While

postgraduate training in pharmacology in the UnitedStates has increased only at the same rate as that in otherpre-clinical disciplines, postdoctoral trainees in pharma-cology are increasing much more rapidly than in otherdisciplines. These postdoctoral trainees are almost all inmedical-school departments, and 72% of them takeacademic posts within one to five years-which is

presumably a good augury for the staffing of the new andbigger medical schools planned for the United States.

If forecasts of the number of doctors needed inBritain within the next few years are justified, then tomeet what may be a 40% increase in medical students,many more preclinical and clinical teachers will be re-quired. This need has probably not been fully includedin PATON’s estimate of demand for pharmacologists, andthat is an extra reason for re-examining the qualitative aswell as the quantitative side of supply and demand.While it may now no longer be true for pharmacologistsas was written of the pedlar 4 (" Where he comes fromnobody knows, Nor where he goes to, but on he goes "),a follow-up study is needed, with further emphasis onthe prospective as well as the retrospective situation, ofman-power and training in pharmacology.

3. Pelikan, E. W. Pharmacologist, 1966, 8, 98.4. Rands, W. B. The Pedlar’s Caravan.

Dental Caries and the Comforter

IN 1911 E. H. R. HARRIES 1 described a type of dentacaries in very young children, and, because they ha(been in the habit of sucking a comforter, he called i" comforter caries," laying the blame on that accursedinstrument". A report 2 in 1927 described this form ocaries in more than 70 children of 3 years and under-and that description has not been materially change(since. Typically, the lesion begins on the labial surfaceof the four maxillary incisors at the gingival margin an(advances towards the incisal edge. Often the first deci.duous molars, which erupt at about 1 year, are als(

affected; but the canines, lower incisors, and seconcmolars are less commonly damaged. Many mothers sa)that the teeth " came through decayed " or decayedsoon after they came through, sometimes within a fewweeks. 51 of the 70 children were breast-fed and 19

bottle-fed, so artificial feeding was not apparently rele-vant. On the other hand, of 74 children of 3 years andunder with this condition, 43 used dummies dipped insome fermentable carbohydrate, 21 were said not to usea dummy at all, and 10 used one, but undipped. Fur-ther questioning disclosed that, in the last two groups,many children had biscuits or sweets when they wentto bed. Favourite anointments to the dummy in 1927were malt extract, condensed milk, honey, sugar, andjam; and 2 mothers used sugar bags. The use of a

dummy is still widespread today, most commonly insocial classes III, IV, and v, and in families where mater-nal care is inadequate.3 In a later inquiry I of 58children with caries, 43 were found to have used dippeddummies or a " comforter bottle " containing a sweet-ened liquid. Of the other 15 children, 12 had receivedseveral times daily for long periods medicines or con-centrates, including undiluted fruit syrups, iron tonics,and linctus; and only 1 was said to have had none ofthese habits.

The well-known Vipeholm work 5 on adults in Swedendemonstrated that the quantity of sugar eaten at mealswas not related to the caries-rate, but between-mealsnacks of sticky sugary food greatly increased dentalcaries. A similarly high correlation was also noted inchildren,6 so it seems that the length of time the sugaris in the mouth is the important point. The infant whofalls asleep with a sweetened dummy, a miniature

feeder, a biscuit, or a sweet in his mouth starts the nightwith the necessary fermentable carbohydrate in hismouth. During sleep the flow of saliva is much reducedand swallowing almost stops 7; hence the contents of themouth may remain there for several hours. Theabsence of damage to the mandibular incisors is attrib-utable to the posture of the tongue during sucking. The1. Harries, E. H. R. Lancet, 1911, ii, 1327.2. Pitts, A. T. Br. dent. J. 1927, 48, 197.3. Spence, J., Walton, W. S., Miller, F. J. W., Court, S. D. M. A Theas

Families in Newcastle upon Tyne; p. 137. London, 1954.4. James, P. M. C., Parfitt, G. J., Falkner, F. Br. dent. J. 1957, 103.375. Gustaffson, B. E., Quensel, C. B., Lanke, L. S., Lundquist, C, Gra

H., Bonow, B. E., Krasse, B. Acta odont. scand. 1954, 11, 2326. Zita, A. C., McDonald, R. E., Andrews, A. L. J. dent. Res. 1959.

860.7. Lear, C. S. C., Flanagan, J. B., Jr., Moorees, C. F. A. Archs

1965, 10, 83.

535

rubber nipple rests against the palate while the tonguepresses against it and is extended forwards to the lips,thus protecting the lower incisors. The canines andsecond molars often escape attack because they are thelast of the deciduous teeth to erupt, at about 18 and 30months. Occasionally, when the caries is atypical,the sucking pattern is also unusual: for example, themother of a boy with rampant caries on the buccal sur-faces of the deciduous molars volunteered that her sonused a dummy dipped in a sweetener and tucked it firstin one cheek and then in the other, along the sulcus. 8

Usually the site first attacked is that area of enamelformed in the neonatal period; and the prenatal enamel(the incisal third of the incisors) is affected only later byspread of the lesion. This postnatal enamel may showmany microscopic defects,2 particularly in children inpoor health, but there is no evidence whether or notthat this has any connection with caries.

The comforter bottle or miniature feeder may betied to the perambulator or even to the child himself;and it usually contains a partially diluted fruit juice orsyrup. In an investigation 9 of the effects of fruit

squashes on teeth, the squashes were diluted in theusual ratio of 1 part in 4 and given to animals as theirnormal fluid intake for from 5 to 8 days. All

squashes eroded the animals’ enamel and also that ofhuman teeth in vitro. Similarly, after reports of com-forter caries in children taking undiluted iron tonicseveral times a day, its effect on teeth was examined invitro. 10 Flaking, etching, and decalcification were seenin proportion to the acidity of the medicine (some tonicshad a pH in the range 1-5-3-52 in the undiluted state).Both the iron tonics and the fruit squashes, then, pro-duced erosion of enamel in the test-tube and in labora-

tory animals-but this is not dental caries. Furtherclinical research may elucidate the possible relationbetween comforter caries and those particular habits.Inevitably, the possible cariogenic action of milk wasalso raised, but the suspicion was shown to be unfounded.The research committee of the Canadian DentalAssociation’s 1958 statement 11 said that the abstractwhich gave rise to this misconception was wrong, andthat several reports indicated that an increase in milkconsumption led to reduction in caries. It has nowbeen shown in vitro that milk gives added protection tothe enamel against acid attack, but that the addition ofsugar to the milk reduced this advantage.12 13Prevention of this type of dental caries is a matter of

education, and simple rules suffice. If a dummy or com-forter is really necessary, then it should never be" sweetened ". The place for vitamin syrups and thelike is in the stomach, not in the mouth. Miniature com-forter bottles should be condemned. For an infant whois hungry at bedtime, milk must surely be the bestsnack. Biscuits and sweets should never be given in bed.8. Porteous, J. R. Personal communication.9 Holloway, P. J., Mellanby, M., Stewart, R. J. C. Br. dent. J. 1958, 104,

305.10 James, P. M. C., Parfitt, G. J. Br. med. J. 1953, ii, 1252.11 J Can. dent. Ass. 1958, 24, 588.12 Jenkins, G. N., Ferguson, B. G. Br. dent. J. 1966, 120, 472.13 Weiss, M. E., Bibby, B. G. Archs oral Biol. 1966, 11, 49.

Towards a Numerate Profession"THE statistician, entering medicine," remarked

MAINLAND (himself a physician but of that per-suasion),

" is not an angel bringing light to a previouslydark continent," for, as he went on to point out,

" inthe past 100 years medicine has made enormous strides,due largely to quantitative methods, but without theaid of formalized statistical ideas or techniques." Onthe other hand, Lord COHEN,2 a clinician par excellence,has paid a graceful tribute to the beneficent influencethat the school of biometricians from KARL PEARSONonwards has had on the evolution of medicine as ascience.

This apparent discordance has been reviewed byREID 3 in this year’s Stephen Paget lecture to theResearch Defence Society. Recounting the great debatebetween Sir ALMROTH WRIGHT and Prof. KARL PEARSON,he pointed to the conflict between the microbiologistconfident in anti-typhoid vaccination and the statisticianwho had doubts about the design and conduct of thefield trials. WRIGHT clearly regarded PEARSON as anignorant and pedantic obstructionist with no under-standing of the vagaries of biological data; and his

biographer, LEONARD COLEBROOK 4 protested thatWRIGHT dealt with probabilities and not certainties, im-plying that PEARSON was looking for mathematical proofin a fundamentally uncertain world. This, however,was less than fair; for PEARSON’S contribution lay in hisinsistence on the regularities of biological variation andthe ways in which that variation could be measured andhow such measurements could then be used to assessthe significance of observations on living things. Hebelieved that the inherent variability of biological obser-vations was no excuse for imprecision in either observa-tion or deduction. He was shocked by WRIGHT’Spassionate advocacy of immunisation when the fieldtrials of the vaccine had been only poorly controlledcomparisons of the morbid experience of selectedvolunteers with that of their comrades in the same

Army units. Although his protests were largely ignoredat the time, his views were ultimately vindicated by thedemonstration in well-controlled trials, conducted afterthe 1939-45 war, that the alcohol-killed vaccine,introduced entirely on the basis of laboratory experi-ments, was much inferior to the original phenol-inactivated type. These trials incidentally underlinedthe hard fact that, with protection-rates of only 73%,immunisation was by no means the panacea that thepioneers proclaimed. Neither side in the debate had a

monopoly in scientific omniscience; but the practicalvalue of cool statistical appraisal emerged clearly.

Since PEARSON’S time, others have developed thescientific approach to design and conduct of biologicalexperimentation in general and clinical trials in particu-lar. Sir RONALD FISHER was the prime mover, introduc-ing such fundamental concepts as balanced experimentaldesigns and the random allocation of subjects to treated

1. Mainland, D. J. Am. med. Ass. 1965, 193, 289.2. Proc. R. Soc. Med. 1965, 58, 659.3. Reid, D. D. Conquest, 1966, 54, 3.4. Colebrook, L. Almroth Wright. London, 1954.