INTRODUCTION 



that this was not so, whilst Birch et al.'^ differentiated the anti-black- 

 tongue and the " P.P." factors from riboflavine and vitamin Bg. In 

 1937, Sebrell et al.^ confirmed the fact that riboflavine did not cure 

 canine blacktongue, whilst W. J. Dann ^ reported that it did not 

 cure human pellagra, and Fonts et al}^ successfully treated two 

 pellagrins with an extract from which the riboflavine had been re- 

 moved. Thus it was clearly demonstrated that riboflavine had no 

 connection with pellagra, except perhaps by way of complicating the 

 condition. 



In spite of the recognition that riboflavine was different from vitamin 

 Bg on the one hand and from the anti-blacktongue and P.P. factors 

 on the other, the situation remained obscure. Three groups of 

 workers ^^ produced " pellagra " in chicks by feeding them on diets 

 that had been heated. The responsible factor was called the filtrate 

 factor to distinguish it from the eluate factor, as vitamin Bg was some- 

 times called, the latter but not the former being adsorbed on fuller's 

 earth. The filtrate factor was shown by C. A. Elvehjem and C. J. 

 Koehn ^^ to be different from riboflavine, but, on the other hand, 

 a filtrate factor concentrate was found by Fouts et al}^ to cure human 

 pellagra and by C. J. Koehn and C. A. Elvehjem ^^ to cure canine 

 blacktongue. The human antipellagra factor was ultimately distin- 

 guished from the filtrate factor by W. J. Dann and Y. SubbaRow,^* 

 who showed that, whilst nicotinic acid cured human pellagra, it did 

 not cure chick pellagra. 



References to Section i 



1. J. Goldberger and R. D. Lillie, U.S. Publ. Health Rep., 1926, 41, 



1025. 



2. B. Sure, /. Amer. Med. Assoc, 1932, 99, 26. 



3. A. G. Hogan and L. R. Richardson, /. Nutrition, 1934, 8» 3^5- 



4. L. E. Booher, /. Biol. Chem., 1937, 119» 223. 



5. J. Goldberger and G. A. Wheeler, U.S. Publ. Health Rep., 1928, 



43, 172. 



6. C. P. Rhoads and D. K. Miller, Science, 1935, 81, 159 ; C. J. 



Koehn and C. A. Elvehjem, /. Nutrition, 1936, 11, 67. 



7. T. W. Birch, P. Gyorgy and L. J. Harris, Biochem. J., 1935, 29, 



2830. 



8. W. H. Sebrell. D. J. Hunt and R. H. Onstatt, U.S. Publ. Health 



Rep., 1937, 52, 235 ; W. H. Sebrell, R. H. Onstatt and D. J. 

 Hunt, ibid., 427. 



9. W. J. Dann, /. Nutrition, 1936, 11, 451. 



10. P. J. Fouts, S. Lepkovsky, O. M. Helmer and T. H. Jukes, Proc. 



Soc. Exp. Biol. Med., 1936, 35, 245. 



11. O. L. Kline, J. A. Keenan, C. A. Elvehjem and E. B. Hart, /. Biol. 



Chem., 1932, 99, 295 ; S. Lepkovsky and T. H. Jukes, ibid., 



