18 



THE VITAMINS 



substances indispensable for nutrition. This statement was given wide 

 circulation in Bunge's Textbook of Physiological and Pathological 

 Chemistry, but never became influential, probably because the evidence 

 upon which it was based was not sufficiently convincing. Limitations 

 of space make it impracticable for us to attempt to review and discuss 

 here the hints which might be gathered from the writings of other 

 authors ^ and which in the Hght of present knowledge can be construed 

 as foreshadowing, rather than as constituting, an effective discovery of 

 vitamins as factors in normal nutrition. 



Fig. 1. — Growth curves of rats with and without the vitamins furnished by 

 small amounts of milk. The lower curve shows the average weight of six rats 

 receiving a diet of purified foodstuffs ; the upper curve that of six similar rats 

 receiving the same diet with the addition of small amounts of milk. Abscissae — 

 time in days; ordinates — average weight in grams. (Courtesy of Professor Hop- 

 kins and the Medical Research Committee of Great Britain.) 



To Hopkins is due, in our opinion, the honor of having first made 

 clear that natural food contains and normal nutrition requires some 

 other substance or substances beside proteins, fats, carbohydrates, and 

 mineral matters. As early as 1906, he had determined and reported that, 

 "no animal can live upon a mixture of pure protein, fat, and carbo- 

 hydrate and even when the necessary inorganic material is carefully 



* Notable among such writings is that of Pekhelharing (1G05) recently recalled by van 

 Leersum, Science, October 8, 1926. 



