20 THE VITAMINS 



growth-promoting property which is not an attribute of the triglycerides 

 themselves but rather of a fat-soluble substance. Both the water-soluble 

 and the fat-soluble growth-promoting substances are fairly soluble in 

 alcohol which accounts for the fact that Hopkins' alcoholic extract of 

 dry milk contained both (or all) of these essentials and supplied ah 

 that was needed for the growth of rats when added to his mixture of 

 previously recognized foodstuffs. The theory soon gained currency that 

 the water-soluble and fat-soluble substances essential to growth were 

 the same as the water-soluble and fat-soluble "vitamins" which prevent 

 beriberi and ophthalmia, respectively. The addition of these vitamins 

 to a diet otherwise consisting of properly selected isolated foodstuffs 

 appeared to provide all that was needed for the grov^h of rats. The 

 normal grovd:h of babies and of young monkeys and guinea pigs (and 

 doubtless of many other species also) required, however, the feeding 

 of sufficient amounts of the antiscorbutic vitamin as well. 



Thus by 1920 it was well established that the normal growth of 

 the young, at least in the human and some other species, demands 

 adequate supplies of at least three substances believed to be identical 

 with the substances which are essential to the prevention of the three 

 "deficiency diseases" of scurvy, beriberi, and the characteristic oph- 

 thalmia. 



Tertninology and Recent Developments 



The names which best expressed the distinctive properties of these 

 three newly discovered nutritional essentials were perhaps "anti- 

 neuritic," "antiscorbutic," "antiophthalmic" substance, respectively. 

 From the standpoint of food chemistry and normal nutrition, however, 

 it seems an unnecessary and generally undesirable circumlocution that 

 a substance having an important role in normal processes should be 

 named according to the abnormal condition which arises when it is 

 absent. Moreover, Funk's term vitamine was criticized both because it 

 implies that these substances are amines, which is not proven in any 

 case and certainly not probable in all, and because the choice of "vita" 

 as a designation was thought by some to carry an exaggerated implica- 

 tion of unique responsibility for life and vitality whereas other sub- 

 stances such as tryptophane are no less essential. But if "vita" seems 

 to claim too much, the designation "accessory" suggested by Hopkins 

 is certainly too modest, since an accessory substance would ordinarily 

 be judged to be dispensable whereas the indispensability of these sub- 

 stances is one of their most marked characteristics. 



In order to avoid these difficulties McCollum suggested that, until 



