McCarrison's noteworthy summary of the functions of vitamins113 very concisely and positively sets forth their bearing on health and disease:

"(1) Vitaminee are constant constituents of living tissues. Although present in very small amounts, maintenance of health is dependent on their action.

"(2) Vitaminee do not themselves contribute to the energy supply of the body but facilitate utilisation by it of proteins, fats, carbohydrates and salts of food.

" (3) Proteins, fats, carbohydrates and salts cannot support life without vita-mines, nor vitamines without these proximate principles; they are complementary to each other. Without vitamines, the body starves.

" (4) A distinct relationship exists between the amount of vitamines required and the balance of food in protein, fat, carbohydrate and salt, the efficacy of the vitamine depending on the composition of the food mixture.

"(5) A distinct relation exists between the amount of vitamine required and the rate of metabolic process.

"(6) Each vitamine plays a specific part in nutrition.

"(7) It appears that vitamine A is associated with the metabolism of lipoids and calcium, as well as with chemical reactions requisite for growth and maintenance.

"(8) Vitamine B appears to be associated with the metabolism of carbohydrates and with the chemical reactions and functional perfection of all cells, particularly nerve cells.

"(9) Vitamine C appears to be associated with the metabolism of calcium and with the chemical reactions of growing tissues.

" (10) All vitamines are concerned in the maintenance of orderly balance between destructive and constructive cellular processes.

"(11) One vitamine cannot replace another although its function may be interfered with by the absence of another.

" (12) The final result of their efficiency is the same whatever be the degree of deprivation, the greater the deprivation the more rapid is the onset of symptoms due to it, the lesser the deprivation the slower is the onset of the symptoms due to it.

"(13) Each vitamine exercises a specific influence on the adrenal glands; the effect of their deprivation on these organs is one of the most outstanding features of deficiency diseases.

"(14) Vitamines influence markedly the production of hormones and all external secretions.

" (15) There is reason to believe that the capacity of any given cell for work is impaired in proportion to the degree of vitamine starvation.

"(16) Vitamines aid the tissues in resisting infection.

" (17) Vitamine, especially vitamine B, induce in the human and animal body a desire for food.

"(18) Vitamines are one link in the ehain of essential substances requisite for harmonious regulation of chemical processes of healthy cellular action. If the link be broken, harmony ceases or becomes discord as it may cease or become discord if any other link be broken.

118 Studies in Deficiency Diseases, Oxford University Press, 1021, Am. Food Jour. Oct. 1021.

"(19) The place of vitamines in human economy must be considered in connection with metabolism as a whole: in connection with their relation to other essential food requisites, with their relation to organ digestion and assimilation, and with their relation to endocrine regulators of metabolic processes".