525

estimated from an equation in which the total " thera- ,

peutic units " multiplied by 100 are divided by thenumber of weeks of treatment, the answer being the so-called " efficiency index." Given that treatment isadministered for the number of weeks recommended forthe stage of the disease, and an efficiency index of 60 ormore, the patient is regarded as having had sufficienttreatment. The average clinician may feel rather

sceptical of this attempt to estimate the patient’sreaction to treatment in terms of a mathematicalformula, but the procedure has stood the test of ColonelBurke’s experience and so commands respect. It maybe questioned whether his classification of the stages ofsyphilis has much advantage over the Ricordian classifi-cation on which fundamentally it is based. Despitethese criticisms the book is able and stimulating. It isto be hoped that it will not be allowed to pass intooblivion as a result of the author’s untimely death.

Miedical Societies

NUTRITION SOCIETYTHE first scientific meeting of the society was held in

the Physiological Laboratory, Cambridge, on Oct. 18.Sir CHARLES MARTIN, F.R.S., took the chair at themorning session and Sir JOSEPH BARCROFT, F.R.S., atthe afternoon session. In an introductory address, SirGOwLAND HOPKINS, F.R.S., pointed out that the needfor a nutrition society had long been felt. The subjectwas becoming so large and its implication so widethat it was no longer practicable to consider it as asubsidiary branch of biochemistry or physiology. Moreimportant perhaps was the need for closer collaborationbetween the laboratory worker and the clinician, betweenthe public-health worker and the dietitian, betweenthose concerned with human nutrition and those con-cerned with animal nutrition. Such cooperation waspossible and a society such as this could bring it about.The secretary, Mr. Leslie J. Harris, D.Sc., read messagesof goodwill from American nutritional workers and manyEnglish societies. The meeting took the form of asymposium on the evaluation of nutritional status.This was discussed under three heads : the assessmentof the level of nutrition in man; the clinical signs ofdietary deficiency; and the nutrition of farm animals.

ASSESSMENT OF LEVEL OF NUTRITION IN MAN

Dr. HARRIS reviewed the laboratory methods whichhave recently been evolved for the study of nutritionalstatus in man. There were many reasons, he said, whysuch tests were of use-they could detect - signs ofdeficiency earlier than was possible by clinical examina-tion ; even if no deficiency existed it was often usefulto determine whether the reserves of a nutritional factorwere high or low ; the final symptoms of deficiency (forexample, avitaminoses C or K) often occurred so sud-denly that it was of considerable advantage to detectthe possibility of their approach ; lastly, the existence ofpartial deficiency in itself, while not necessarily causingobvious signs or symptoms, must result in some degree ofill health. Dr. Harris brought forward evidence for thereality of " partial deficiencies." The fact that frankberiberi or scurvy were rare in this country, or even thatcursory examination revealed no sign of malnutrition,was not sufficient to prove that partial deficiency did.notexist. The standards used in assessing malnutritionwere often either inadequate and variable-such as themethod of classification of nutritional status in school-children-or were too low, as for example were the pastweight and height averages for children. The adminis-tration of iron to " normal " babies or of extra milk to" normal " school-children has resulted in considerableimprovement in health and physique. He then des-cribed the methods which were available for the detectionof partial deficiencies of different dietary essentials andgave examples of their use. By the urinary excretionmethod (the so-called " saturation " test) of measuringvitamin-C reserves it was shown that school-children in apoor district in Cambridge were lower in respect of vita-min-C nutrition than those from a well-run home forwaifs and strays where the diet was adequate. Thereserves of the vitamin were also found to be higher atthe end of the summer than in the early spring. Large

groups of children given various graded supplements ofvitamin-C showed corresponding graded levels in their" reserves " as measured by this method. Low levels of

vitamin C were found in patients with acute infectiousdiseases, in those on " gastric diets," and in lower econo-mic classes. Tests such as these were being developedalso for vitamin B and nicotinic acid, and they offereda reliable method of obtaining exact information aboutthe ’level of nutrition of individuals or groups ofindividuals in the community in respect of specificnutrients.

Dr. H. M. SINCLAIR spoke of the necessity for cautionin interpreting the results of saturation tests. Altera-tions in renal threshold, rate of storage or rate of meta-bolism might conceivably affect the quantity of vitaminexcreted in the urine, apart from the degree of saturationof the tissues. The postabsorptive level of a givenvitamin in the blood was probably of greatest physio-logical significance since this determined the amountavailable to the cell. In attempting to assess accuratelythe nutritional status of individuals or groups, an exhaus-tive investigation was essential-clinical, clinico-labora-tory and special tests in blood and urine. He gaveexamples of the methods by which nutrition surveys ofthis sort were being conducted in America.

Dr. JOHN YUDKIN gave an account of some recentsurveys of the incidence of dark adaptation which hehad been carrying out in collaboration with Mr. G. W.ROBERTSON, B.Sc. Poor dark adaptation in singleindividuals may be proved to be due to deficiency invitamin A by the improvement which occurs when thevitamin is given. In comparing large groups of people,however, a comparison of the proportion in each groupwhose dark adaptation is good, bad or indifferent issufficient to show the relative status of these groups asregards vitamin-A intake. Thus, in a study carried outin children from three Cambridgeshire schools, 60% ofthe children from two of the schools, and only 35% fromthe third school, were classed as having good darkadaptation. In adults, it is necessary to compare groupsof similar age since there is a deterioration of darkadaptation with age. In three groups of young peoplebelow the age of 22, two of them-nurses and medicalstudents-showed 80-90% who had good dark adapta-tion, while the third-workers in a Midland factory-contained only 55% in this grade. The factory workerswere also examined as to their haemoglobin levels.Nearly 800 subjects were investigated ; more than 30%of the women and some 6% of the men had definitenutritional anaemia.

°

CLINICAL SIGNS OF DIETARY DEFICIENCY

Dr. B. S. PLATT stressed the point that the nutritionallevel at which clinical symptoms appeared was definitelylower than that at which optimal health is maintained.The detection of deficiency diseases rested not only onaccurate examination but also on the response to specifictherapy or on the improvement following a generallyincreased standard of nutrition. Illustrating his remarkswith photographs, Dr. Platt pointed out some of thefeatures of deficiency diseases as seen by him in Chinaand Africa. In some instances the introduction ofsome simple’ dietary measure produced impressiveresults. The change, for example, to unwashed fromwashed rice in certain factories in Shanghai led to aconsiderable fall in the number of employees who had togive up their work. Dr. Platt emphasised the associationbetween deficiency and infection. He referred also tothe high incidence of infestation with the bed-bug foundin people suffering from cheilosis. Finally, a greatdeal might be learned from the study of the generalbehaviour of subjects : the apathy and listlessness foundin malnourished children contrasted greatly with theexuberance and high spirits of their better nourishedneighbours.

Dr. R. H. DOBBS dealt with the assessment of thenutritional status of children. Adequate assessmentmust be made on the basis of physical examination,general behaviour (particularly as described by themother and teacher) and the existence of special evidenceof malnutrition. Of particular value in the physicalexamination was the condition of the skin, the muscula-ture (including stance and posture) and the teeth.Apathetic behaviour, poor appetite and undue fatigu-

526is

ability would affect school progress and afforded a guideto general ill-feeding. Malnutrition might also be isus-pected from " external evidence " such as the familyincome or a history of artificial feeding without due careto supplement the diet with, for example, iron in oneor other form. Conditions of stress were important inaccentuating the effects of defective nutrition. Growthin childhood provided such stress and infection increasedit, making it all the more important to assure theadequate nutrition of the child.The question of physiological stress was underlined by

Dr. W. C. W. NIxON. The increased demands of the bodyduring pregnancy might well be sufficient to reveal aborder-line state of deficiency. In Hong-Kong, beriberifrequently made its appearance during the latter half ofpregnancy. Vomiting in the early stages might increasethe deficiency of vitamin B,. Such mild and oftenneglected complications of pregnancy as oedema andpins-and-needles might well be due to mild deficiencyof this vitamin. Many women dying of beriberi duringpregnancy had had cedema for a month or two before thediagnosis was obvious. Recalling the incidence duringpregnancy of dental caries, anaemias, cramps, cedema,fatigue and pins-and-needles, Dr. Nixon asked whether,in the light of newer nutritional knowledge, it was notmore likely that they were all signs of inadequate nutri-tion rather than necessary physiological concomitantsof the pregnancy state.

"

NUTRITION OF FARM ANIMALS

Mr. C. CROWTHER, Ph.D., began by comparing theproblems of animal nutrition with those of humans.The nutrition of farm animals was concerned chieflywith attaining as economically as possible a specificproduct. This dicl not necessarily involve the optimalnutrition of the animal and indeed might intentionallyproduce a pathological state. The worker in animalnutrition had many advantages over his colleaguesstudying human nutrition. His subjects offered a muchgreater freedom in experimentation, were more passiveand hence less likely to interfere in the experiments, andlastly were much more uniform as regards geneticconstitution. On the other hand, in determiningthe adequacy of an animal diet it was difficult toassess the quantity of available carbohydrate sincecellulose was in part assimilable. The problem of theprotein, too, was complicated in ruminants by thebacterial synthesis of non-protein nitrogen into amino-acids. The calculation of the energy value of the dietwas also more involved than with human diets. Theproblem of supplying specific sources of vitamins did notoften arise in the nutrition of the farm animal, especiallywhen grazing. In considering the effects of such

supplements, it was necessary to bear in mind the otherconstituents of the diet, since their effects were oftenmore than simply additive.

Mr. H. H. GREEN, D.Sc., reviewed some of the com-moner deficiency diseases of animals. Vitamin defici-encies were not common except in animals intensivelyreared in stables, batteries or styes. In such conditions,deficiency of vitamin D might occur in poultry and ofnicotinic acid in pigs. Mineral deficiencies, on the otherhand, were not uncommon. Aphosphorosis, for example,was well known in South Africa. Deficiency of the traceelements-copper, cobalt and possibly manganese-alsooccurred. Swayback disease amongst lambs appearedto be due to deficiency of copper, and possibly also ofcobalt.

Mr. JOHN HAMMOND, D.Sc., F.R.S., discussed thequestion of the total energy and protein of the diet.Animals kept on a low plane of nutrition for a short whileafter birth are not only smaller than normal at the endof this period but go on being small into adult life. Theweight of animals fed for long periods on a low plane ofnutrition may be less than half that of litter matesreceiving a larger amount of food. Not only the sizeof the body but also the relative proportions of the differ-ent parts are greatly affected by controlling the foodintake at different levels. These effects, too, produced inyoung animals, may persist to adult life even if the diethas subsequently been increased.

DISCUSSION

Prof. J. L. MAXWELL, M.D., stressed the importance ofdetecting early signs of deficiency. He suggested that

pain in the back and legs, and instability in walking oftenoccurring in pregnancy were possibly early signs ofvitamin-D deficiency. It was necessary also to bear inmind that deficiencies were likely to be multiple ratherthan single.

Prof. E.-J. BIGWOOD said night-blindness in Austria in1918 appeared first in pregnant women, another exampleof the effect of pregnancy revealing a latent deficiency.In a prisoners’ camp in Germany the Russians developedscurvy and the Rumanians developed pellagra althoughall were given the same deficient diet. With regard tothe question of saturation with a factor such as vitaminC, it had often been asked whether this was necessarilyidentical with the optimal intake. If guineapigs, one ofthe few species of animals which can develop scurvy, areallowed a free choice of diet they become saturatedwith vitamin C. Moreover, the amount of the vitaminin the blood reaches the same level as that of other’ species of animals in whom scurvy cannot be pro-duced but for whom nature synthesises the requisitevitamin C.

Dr. DAGMAR WILSON appealed for the standardisationof the signs of early deficiency so that workers could betrained, as in India, to recognise them easily. She hadbeen able to recognise several cases of angular stomatitisin Oxfordshire school-children.

Mr. GEOFFREY BouRNE, D.Sc., pointed out that amongthe early signs of vitamin-Bi deficiency were increasedirritability, lassitude and a general deterioration inmental alertness. In the detection of early deficiencyhe had found the Gothlin test for capillary fragility of usein showing a lowered intake of vitamin C in patients withpeptic ulcer.

Mr. S. K. KON, D.Sc., suggested that a further testfor malnutrition was the estimation of vitamins in themilk of nursing mothers. Tests already begun showedthat there was a considerable drain on the vitamin-Areserves of the mother and that the amount of vitamin Cis now considerably lower than that found in 1934 byDr. Harris.

Prof. H. D. KAY, D.Sc., said that although,as Dr.Crowther had pointed out, the provision of extra suppliesof vitamins was not perhaps essential for all classes offarm animals, it would considerably affect the nutritivevalue of the animal product as far as their use in humannutrition was concerned. Thus, the amount of vitaminA in milk was dependent to a very large extent on theamount ingested by the cow.

Prof. OTTO KESTNER recalled some of his work onprotein deficiency in Germany in the last war. ’ He alsopointed out that while vegetable proteins might singly beof low biological value, together they might act comple-mentarily so that defects in one might be made goodby another.

Dr. S. W. SWINDELLS hoped that one of the objectsof the new society would be to disseminate accurateknowledge of nutrition.

Dr. E. H. WILKINS looked forward to the adoption ofsimple tests for malnutrition and mild deficiencies whichwould be easily applicable by medical officers of health.He instanced the importance of a study of posture inchildren as a guide to nutritional status.

Dr. ROBERT SUTHERLAND wished to see emphasisedaspects of nutrition which would lead to the adoption ofgenerally satisfactory diets, rather than those which ledto the development of studies of deficiency diseases, theirassessment and their specific cure.

Sir JOSEPH BARCROFT, referring to the present statusof laboratory methods in the diagnosis of deficiencydisease, recalled the similar position which arose afterthe introduction of such diagnostic aids as the electro-cardiogram by Mackenzie and Lewis. Clinicians wereat first sceptical as to their usefulness, but this wasmainly because the apparatus was costly and the tech-nique specialised. He felt that laboratory methods inthe study of malnutrition would soon reach a state ofrecognition and applicability comparable to that enjoyedtoday by the technical methods used in cardiology. Asfar as the question of the separate study of the variousnutritive factors was concerned, he felt no apprehensionthat this would detract from a proper study of malnutri-tion as a whole. He looked forward to the time when weknew enough about nutrition to construct a completelysynthetic diet.