632 METABOLISM, NUTRITION AND DIETETICS 



bered that there is no stimulant which is not liable to be abused. 

 It has been shown by ergographic experiments (p. 750) that, likj 

 alcohol, tea, coffee, mate, and cola-nut, which all contain the alka- 

 loid theine or caffeins, restore the power of performing muscular 

 work after exhaustion, but only if food has been recently or is 

 simultaneously taken. 



Vitamines. Certain substances, although neither in the ordinary 

 sense foods nor condiments, seem to be necessary for the main- 

 tenence of health, for in circumstances in which these cannot be 

 obtained for long periods so-called ' deficiency diseases,' such as 

 scurvy, are liable to occur. Scurvy used to be the scourge of the 

 sailing-ship in the days when fresh meat, and particularly fresh 

 vegetables and fruits, were unobtainable on long voyages. It has 

 long been known that it is prevented by the use of lime or lemon- 

 juice, in which citric and a trace of malic acid are contained, and 

 it used to be thought that it was the organic vegetable acids which 

 were the important thing. Recent researches have shown, how- 

 ever, that scurvy is only one of a group of diseases, including beri- 

 beri, and probably pellagra, rickets, and others which are induced 

 by deficiency in the food of certain substances minute in amount 

 but essential to proper nutrition. 



The importance of such accessory components in the food has been 

 already pointed out, in discussing the influence of artificial diets upon 

 the growth and maintenance of animals (p. 617). These substances are 

 sometimes termed ' vitamines.' But their chemical nature is im- 

 perfectly known, and there is no evidence that the bodies which exert 

 the beneficial influence belong to the same chemical group.* 



McCollom prefers to designate provisionally the two substances or 

 groups of substances essential, in addition to a diet of purified proteins, 

 carbohydrate, fats and inorganic salts, for growth and maintenance of 

 rats, as ' fat-soluble A ' and ' water-soluble B, ' rather than to use the 

 unsatisfactory term vitamines. The first is soluble in fats and is 

 abundant in butter-fat, egg-fat, and ether extract of kidney. It is also 

 found in considerable amount in the leaves of plants, but is represented 

 in the seed in too small amount to supply the needs of a young animal. 

 The second, which is soluble in water and in alcohol, is plentifully 

 present in wheat, wheat germ, maize, alfalfa leaves, cabbage, and in a 

 number of foods of animal origin. 



One representative of the important food constituents in question is a 

 basic substance separated by Funk from the polishings of rice, and 

 named by him, ' vitamine.' Polished rice is rice deprived of the outer 

 coats by modern milling processes, and the polishings are the coats which 

 have been removed. Since the introduction of steel rollers instead of the 

 primitive millstones which used to crush the whole grain, beri-beri, a 

 disease characterized by inflammatory and degenerative changes in the 



* It might be better in the present state of our knowledge to avoid giving 

 those bodies a name which may easily mislead. They might possibly be pro- 

 visionally spoken of as " vitines," a term involving no assumption as to their 

 chemical nature, and implying only their importance in the nutritional pro- 

 cesses associated with the life (and growth) of the tissues. 



