CHAPTER II 

 THE ROLE OF VITAMINES IN THE ANIMAL KINGDOM 



Coming to this important chapter, we must first of all satisfy our- 

 selves as to the relative importance of the vitamines in nutrition. 

 In fact, the role of the vitamines is placed in the foreground by some 

 investigators, so much so, that the impression prevails that these 

 substances can completely compensate for all dietary deficiencies. 

 Obviously, this is not the case. The requirements of the animal 

 organism for each of the food constituents have been determined 

 chiefly in dogs, and lately in rats; we need only refer the reader to 

 the modern text books on the science of nutrition if he wishes to study 

 the question more thoroughly. We must specifically emphasize, as 

 we did in the first edition, that most of the old and many of the new 

 experiments on this subject were not entirely convincing, since the 

 investigators were either unaware of the existence of the vitamines or 

 else ignored their significance. In the last six years, however, many 

 of the experiments were repeated, bearing in mind the progress that 

 had been made in vitamine research. The conclusions arrived at in 

 these experiments, for example, for rats, are as follows : For complete 

 nutrition, these animals need, above all, a biologically complete 

 protein a protein of high biological value one containing all of the 

 necessary amino acids; further, a carbohydrate of the nature of 

 starch, sugar or dextrin; a certain amount of fat, a salt mixture, so 

 chosen that it contains the necessary cations and anions in proper 

 proportion; and finally vitamines A and B. 1 It must be held open 

 for further investigation to determine whether or not rats can get 

 along on a complete protein, a salt mixture and vitamines (without 

 carbohydrate and fat) ; for some animals, like the dog or cat, which 

 can get along on meat alone, this has already been definitely estab- 

 lished. The series of experiments by Spriggs (192) and Maignon 



1 Parsons (191a) recently found that rats do not require a supply of 

 vitamine from outside sources. In spite of the lack of this vitamine in the 

 diet, the organs spleen, kidney and muscles of rats so fed contain appre- 

 ciable amounts of vitamine Cwhen tested on guinea pigs in the form of extracts. 

 Whether this vitamine C originates from the vitamine B of the diet has to 

 be left for future demonstration. 



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