DIET AND NUTRITION" 



ments, but the appetite improves immediately on ad- 

 ministering the extract containing the vitamin. All species 

 of animals appear to require this vitamin. 



Vitamin B is abundant in yeast, in germs of cereals, and 

 in the leaves of young plants. It occurs generally in tubers, 

 roots, fruits, leaves, cereal grains, milk, eggs, and the 

 glandular organs of animals. Muscle meats are almost 

 lacking in it; and refined cereal products, such as white 

 flour, degerminated corn meal and polished rice, the sugars, 

 starches, and fats from both animal and vegetable sources 

 are devoid of it. Recent studies by Macy, in which careful 

 assays of both human and cow milks were made by feeding 

 tests with young rats, have shown that about seven times 

 the volume of milk is necessary to provide the minimum of 

 vitamin B on which approximately normal growth can 

 take place than is required to furnish an adequate amount 

 of vitamin A. Her studies suggest that infants restricted 

 solely to a milk diet during the first six months of life are 

 developing on the minimum intake of vitamin B on which 

 growth would be possible. It appears that infants would 

 probably fare better if their milk were fortified with some 

 concentrate containing this vitamin. 



Vitamin C. Vitamin C is the anti-scorbutic principle. 

 This is the most unstable of the vitamins and is especially 

 susceptible to destruction by contact with the oxygen of 

 the air. Birds apparently do not require this vitamin, and 

 this has also been demonstrated for the rat. In these species 

 the body has the capacity to synthesize the vitamin from 

 some other component of the diet, since the livers of rats 

 grown to maturity on diets free from C are very potent in 

 curing acute scurvy in guinea pigs. 



Deficiency of vitamin C produces characteristic patho- 

 logical changes. It appears that the endothelial cells lose 

 their power to produce the cement substance which holds 

 them together; and so the capillary blood vessels, whose 



[371] 



