350 CARL VOEGTLIN 



Driunmond(rf) (1918) studied the metabolism of rats fed on an artifi- 

 cial diet deficient in antineuritic vitamin and noted the presence of ereatin- 

 uria, accompanied by decrease in food consumption. The addition of the 

 vitamin to the diet was followed by an increased food intake. 



Incidentally, reference is made to the work of Mellanby (c) (d) (1919), 

 who claims to have produced experimental rickets in dogs by means of a 

 diet deficient in fat-soluble vitamin, which would indicate that the sub- 

 stance is concerned in the metabolism of calcium. It is impossible to ac- 

 cept this view without considerable modification, as Hess and linger (/) 

 (1920) have shown conclusively that infants develop rickets while receiv- 

 ing "a full amount of this principle, and that they do not manifest signs, 

 although deprived of this vitamin for many months, at the most vulnerable 

 period of their life." McCollum and Simmonds (1920) have also pre- 

 sented evidence which is not in agreement with Mellanby' s views. 



A lack of fat-soluble vitamin in the diet leads to the appearance of 

 xerophthalmia in rats (McCollum) ; a condition which had previously been 

 observed by Mori (1904) in young children whose diet was lacking in 

 certain fats, which are now known to be rich in fat-soluble vitamin. 



The antiscorbutic vitamin is probably concerned in the growth of some 

 species, but not of all, as Hess(c) (1916) observed the appearance of scurvy 

 in infants in spite of a preceding period of normal growth. Hoist and 

 Frohlich have described great fragility of the bones in guinea-pigs suffer- 

 ing with scurvy which on histological examination was shown to be due 

 to lack of proper calcification. It would thus appear that the antiscorbutic 

 vitamin has some relation, either direct or indirect, to calcification. 



To sum up, very little indisputable knowledge is available as to the 

 part played by vitamins in metabolism beyond the fact that the antineu- 

 ritic and fat-soluble vitamin are needed for growth and that all three 

 vitamins are essential for proper nutrition of man and some of the higher 

 animals. Taking into consideration that apparently very small amounts 

 fulfil the physiological requirements, it is quite possible that vitamins act 

 as catalysts of some metabolic reactions. They may also possess an indirect 

 effect upon nutrition by stimulating the digestive organs in the way 

 indicated above. 



End Metabolism of Vitamins 



The available evidence regarding the ultimate fate of vitamins in the 

 animal body does not permit many positive conclusions. The only data 

 with a bearing on this point are a few observations on the vitamin content 

 of the various secretions and excreta. Muckenfuss (1918) treated saliva, 

 ox bile and human urine with fullers' earth and fed these samples of 

 fullers' earth to pigeons showing acute symptoms, as a result of a polished 

 rice diet. Improvement was noted when the preparation was given in 



