VITAMIN C 157 



In a paper published simultaneously with that of Cohen and Mendel, 

 Hess and Unger (1918a) furnished further evidence that, in the guinea 

 pig, scurvy develops upon diets containing both "fat soluble A" and 

 "water soluble B" in sufficient amounts to guard against deficiency of 

 either of these vitamins. 



The Vitamin C Requirements of Different Species 



The universal acceptance of the vitamin hypothesis as related to 

 scurvy was doubtless retarded by the fact that rats, which require 

 both vitamin A and vitamin B for successful nutrition, do not show 

 symptoms of scurvy when subsisting on diets which in human subjects, 

 monkeys and guinea pigs cause this disease. Harden and Zilva (1918c), 

 however, from studies of the growth and health of rats kept upon 

 diets lacking each in turn of the three vitamins, concluded that "rats 

 existing on a scorbutic diet, although capable of gaining in weight and 

 reproducing themselves, without any apparent manifestation of path- 

 ological symptoms for months, do not thrive so well as animals which 

 have their diets supplemented with an antiscorbutic. This suggests that 

 although rats are not very susceptible to scurvy they cannot absolutely 

 dispense with antiscorbutics without restriction of their normal develop- 

 ment." 



These conclusions were confirmed by Drummond (1919) in feeding 

 experiments with rats through two generations. Larger numbers of 

 litters of young were obtained from the females which received the 

 added antiscorbutic, which was given in the form of orange juice. 

 Drummond concluded from his observations that "the rat requires the 

 antiscorbutic factor in order to achieve a normal development, and 

 that although the requirements of this species are of a very much 

 smaller order than those exhibited by man, the monkey, or the guinea 

 pig, they are sufficiently well marked to dispel any idea that there exists 

 a fundamental difference in the nutritive requirement of the two types 

 of animal." 



This argument might also apply to the evidence reported by Findlay 

 (1921d) concerning the need of rabbits for vitamin C. Rabbits when 

 fed oats, bran, and water did not develop typical symptoms of scurvy, 

 although there was some evidence of congestion of the internal organs 

 on autopsy. This condition, together with the fact that the animals lost 

 weight on this diet, but showed prompt gain in weight if rutabaga juice 

 was administered as an antiscorbutic, led Findlay to conclude that 

 the nonsusceptibility of the rabbit to scurvy must be looked upon as 

 relative rather than absolute. 



