40 THE VITAMINES 



phosphorus. The question as to the nitrogen content of butter has 

 not been touched upon for some years, since the solution of the 

 problem could only be obtained through a purification of vitamine A. 

 In this connection, the amount of lecithin in butter, based upon the 

 phosphorus content, was calculated to be 0.017 per cent by Wrampel- 

 meyer (84) and from 0.04 to 0.07 per cent by Supplee (85) ; the latter 

 also demonstrated the presence of choline, trimethylamine, and 

 ammonia. 



While Osborne and Mendel, as well as McCollum, regarded butter 

 and certain other fats as the only growth-promoting substances, 

 Funk and Macallum (86) went to the opposite extreme, stating that 

 vitamine B was the only growth-promoting substance. It appears 

 from the newer investigations, as we have always believed, that 

 vitamine B is far more important to life and is required in greater 

 amounts then vitamine A. Nevertheless, both substances are 

 necessary for growth as has been developed by the above controversy. 

 The Funk-Macallum experiments showed that butter, when added 

 to an artificial diet, does not cause growth, and it appeared that an 

 addition of yeast was imperative. To be sure, there was then no 

 apparent difference in the efficacy of butter and lard, but it should 

 be said here that in our investigations we found it necessary to add 

 a large amount of yeast in order to obtain good results; fresh yeast 

 worked better than dried yeast. It is not impossible that yeast, in 

 the fresh condition, contains some vitamine A; on the other hand, in 

 the light of the results obtained by Daniels and Loughlin (87), it is 

 possible that some fats, till now looked upon as vitamine-free, contain 

 enough of this vitamine to stimulate growth in rats. 



In this manner, the existence of two vitamines, A and B, was 

 definitely established. In addition, it became apparent that the 

 substance playing the greatest part in the growth of rats is either 

 identical with the antiberiberi vitamine or belongs to the same type. 

 Coming now to vitamine C, its individuality and its differentiation 

 from the other two vitamines was determined in the following 

 manner. While we find vitamine C often associated with vitamine B 

 in Nature, there are products such as egg-yolk and cereals, which 

 are very poor in vitamine C but especially rich in vitamine B. The 

 evidence of their dissimilarity may be seen more clearly in the work 

 of Seidell (88), who showed that vitamine B could be adsorbed quan- 

 titatively with Lloyd's reagent (fuller's earth). Harden and Zilva 



