338 HUMAN BIOLOGY 



blue varieties of corn, etc. do not contain it. It is nearly 

 absent from cereals and absent from such refined cereal 

 products as white flour, corn meal, pohshed rice, etc. 



Vitamin b is most abundant in yeast, wheat germ, rice 

 pohshings, and various leaves of plants. It is relatively 

 abundant, however, in whole grains, peas, beans, tubers, 

 roots, and fruits of all kinds. It is less abundant in milk 

 and scarcely present in muscle types of meats, although 

 abundant in glandular organs, such as liver, kidney, etc. 

 It is essentially lacking in the refined cereal products. 



Vitamin c is contained in fresh raw fruits and vegetables 

 of all kinds, but is especially abundant in the juice of lemons 

 and other citrus fruits, and fresh green leaves such as 

 cabbage, lettuce, etc. It is found in small amount in winter 

 milks, is more abundant in summer milks, is nearly lacking 

 in lean meats but the raw glandular organs contain it in 

 fair abundance. No dry grains or other plant seeds contain 

 the principle but it is rapidly generated in liberal amounts 

 when seeds are germinated or caused to sprout. During 

 cooking, vitamin c is destroyed, principally because of its 

 ready oxidizability. It can be heated to fairly high tempera- 

 tures provided oxygen is excluded. In the process of canning 

 the smothering of the fruit or vegetable in syrup or juice dur- 

 ing the interval while the cans are in the exhaust box causes 

 them to undergo a gradual heating process which accelerates 

 for a time the rate of internal respiration, which tends 

 rapidly to use up the oxygen dissolved in the tissues. After 

 this is efi^ected subsequent heating does not tend to destroy 

 vitamin c. Canned goods, therefore, are superior generally in 

 this respect to foods of all kinds which are cooked under ordi- 

 nary kitchen conditions; the latter tend to destroy practically 

 completely all of the antiscorbutic vitamin c. 



Vitamin d is found in large quantities only in the liver 

 oil of fishes. It is most abundant in pufl"er liver and slightly 

 less so in the liver of the cod and the haddock. These two 

 fish oils furnish the principal source of this vitamin. 



There is growing evidence that vitamin d is a modification 

 of some sterol, a relative of cholesterol. Ergosterol, from 

 ergot, yeast and other fungi, is, when irradiated, the most 

 active substance known in the prevention or cure of rickets. 



