214 THE VITAMINES 



dition is controlled with difficulty in pigeons and chickens, because 

 of the scattering of the food and the ease with which they vomit. 



It would, therefore, be desirable to repeat these experiments on 

 rats, in which it is easy to control the food. Such experiments, 

 which were carried out by Funk and Dubin (I.e. 331), and which con- 

 firmed in general the results with pigeons, will be described in another 

 chapter. Whether our view, that vitamine B plays an important 

 role in carbohydrate metabolism, may be regarded as correct must 

 remain for the future to show, since simultaneously with an enrich- 

 ment of the carbohydrates in the form of starch or sugar, there is a 

 decrease in protein. That protein plays a particular role in nutrition, 

 is well known. Maignon (564) fed rats on diets which varied con- 

 siderably in their protein, starch and fat content, but unfortunately 

 the vitamines were not provided for. While each of the protein-fat 

 combinations could maintain the animal at a constant weight for 50 

 days, this was true of the protein-starch mixture only when both 

 components were present in equal quantities. From this, it was con- 

 cluded that protein is better utilized in the presence of fat than in 

 that of starch. The best nutrition was observed when a mixture 

 consisting one one part protein, one part fat and 1.33 parts starch 

 was fed. Bierry and Portier (565) obtained similar results, and 

 expressed the view that there must be a very definite relationship 

 between the protein and fat of any diet. Bierry (566) noted that 

 disturbances in metabolism could be prevented only when the individ- 

 ual dietary constituents were present in proper proportions. 



While we believed, at first, that the delaying effect of a protein 

 addition on the development of beriberi was due to the presence 

 therein of vitamine B, this view is perhaps no longer tenable. We 

 shall see later that the "vitamine sparing" action of protein, or the 

 presence of a special substance essential to life may play a part in 

 this phenomenon. For this reason, we must be conservative with 

 our conclusions when extra protein is added to the diet. To illustrate, 

 let us consider the work of Johns and Finks (567), who investigated 

 the nutritive value and B-vitamine content of war bread, which 

 was milled to the extent of 74 per cent. Working with rats, they 

 found that the above food contains sufficient B-vitamine but not 

 enough protein, since the animals resumed normal growth on the 

 addition of casein. This conclusion is perhaps not quite correct, 

 for the growth-inhibiting influence may possibly still have been due 



