UTAH ACADEMY OF SCIENCES 251 
physiological action. Based upon their effect in the body 
three vitamines are at present recognized: (1) Fat- 
soluable A, essential to growth, occurring with, if not 
actually dissolved in, fats from certain sources, as butter- 
fat, cod-liver oil, egg yolk, green leaves, and certain other 
foods. (2) Water-soluable B, essential for growth and 
for the prevention of beri-beri. It is rather widely dis- 
tributed in nature, occurring in abundance in yeast and the 
germs of most seeds, fruits, many vegetables, greens, and 
other food materials. (3) Water-soluble C, or the anti- 
scorbutic vitamine, prevents and cures scurvy. It is pres- 
ent in living vegetable material as greens and to a smaller 
amount in roots and tubers. Orange, lemon and tomato 
juice contain it in abundance. 
FAT-SOLUBLE A, 
Function.—Fat-soluble A, as mentioned above, is 
essential to growth. Continued lack of this factor results 
also in xeropthalmia, or keratomalacia, a disease of the 
eye which may ultimately result in blindness. It is 
thought by some investigators that rickets may also result 
from lack of this factor in the diet. Others feel just as 
strongly that absence of this vitamine is not a cause of 
rickets. Some recent work by McCollum, however, re- 
ports increased deposition of calcium in the bones in cases 
of rickets, even on low calcium rations, upon the addition 
of fat-soluble A in cod-liver oil. In human rickets the 
calcium content of the blood remains approximately nor- 
mal though the bones seem to lose their power to metab- 
olize it. Whatever the cause of rickets, however, it has 
been shown rather conclusively that it can be prevented 
and cured, with rare exceptions, by cod-liver oil, which 
seems to be practically a specific for the disorder. In- 
creased calcium utilization, even on lower calcium intake, 
has also been observed when cows have been turned from 
a dry ration to green pasture. 
Occurrence. —Butter fat is the standard and usually 
the most convenient source of this factor, though its 
amount in butter fat depends upon the amount of A in 
the feed of the cow, being less on winter and dry rations 
than on summer grass. Cod-liver oil is also relatively 
