VITAMINS — HOPKINS 273 



Some, at least, of the conditions which are now grouped as defi- 

 ciency diseases are of world-wide importance, and though the clear- 

 cut symptoms which the experimentalist can observe in animals un- 

 der strictly controlled conditions are often obscured by intercurrent 

 infections or other complications in clinical cases, yet once a food 

 deficiency has been recognized as an essential link in the chain of 

 causation the method of cure becomes in every case as certain as it 

 is logical. On the other hand, once the hygienist has become con- 

 vinced that this or that disease is really due to faults in the diet of 

 communities its prevention, with or without administrative action, 

 should be easy to secure. Although a defect in the supply of a 

 vitamin, if serious and continued, may result in actual disease, it is 

 in Great Britain more important to realize that a suboptional supply 

 of any essential food constituent cannot fail to induce subnormal 

 health which, especially when induced in childhood, may leave 

 permanent disability. 



Apart from its own inherent importance, the revelation of the 

 significance of vitamins can fairly be said to have directed closer 

 attention to the nutritional importance of other minor constituents 

 of natural foods. The specific needs of the body are proving to be 

 numerous, and lack of materials called for in very small amounts 

 are proving to be just as important to final issues in nutrition as 

 are those required in much larger amounts. This applies to the 

 mineral as well as to the organic constituents of food, and ill-assorted 

 diets may be deficient in the former no less than in the latter. 



For the progress of scientific knowledge concerning these needs, 

 each separate factor has called, and continues to call, for separate 

 and intensive study; but the demands of right nutrition need to be 

 viewed as a whole. We need to know what should be the ideal bal- 

 ance among the many essentials, and how best to secure that it shall 

 be approached in the food supply of ail classes of the community. 

 Short of this, we have today sufficient knowledge to be sure that 

 malnutrition in its subtler aspects often accounts for disabilities 

 which have hitherto been ascribed to constitutional defects or to 

 other circumstances. With present knowledge, moreover, it should 

 be easy, economic questions apart, to prevent such malnutrition 

 everywhere. There is almost sufficiency in the statement that cer- 

 tain foods often held to be luxuries have to be recognized as neces- 

 sities for all. Recognition of this bears upon all the problems of a 

 national food supply; upon production, preservation, transport, and 

 distribution. 



It is interesting to remember that the effective development of 

 the recent knowledge concerning the more subtle aspects of nutrition 

 has been almost coterminous with the reign of King George. 



