VITAMIN B {B,) 45 



Their attempts to concentrate torulin still further by the method 

 of Jansen and Donath proved unsuccessful. In commenting upon this, 

 Kinnersley and Peters say, "We lay no stress upon our failure to con- 

 centrate torulin in our fractions by a method applicable to the pro- 

 tective (? antiberiberi) factor in rice polishings. Doubtless it lies in 

 some peculiarity of the yeast extracts. It is, however, possible that 

 the antiberiberi factor is distinct from torulin. The question at issue 

 seems to be v^hether torulin is distinct from the antiberiberi factor, 

 and what relation these properties of extracts bear to the protective 

 factor in the sense of Jansen and Donath. It is indeed possible that 

 the train of symptoms cured by torulin can only arise when absence 

 of some other factor has accentuated a special phase of metabolism. 

 This would explain certain abnormal responses to test doses, and 

 would also justify the feeling that curative tests upon pigeons are not 

 a reliable guide where human beriberi is concerned." 



This uncertainty concerning the identity of the "curative" and 

 "protective" substance for pigeons was accentuated by the evidence 

 which by this time had become convincing through the various studies 

 reviewed in detail in the following chapter that yeast and other sources 

 of vitamin B contain at least two separate factors for rat growth dif- 

 ferentiated in part by their unlike stability to heat and that (see Chick 

 and Roscoe, 1927; Roscoe, 1927) the thermolabile factor is present 

 in concentrates of the curative substances for pigeons. With the pro- 

 visional designation of the thermolabile and thermostable factors as 

 vitamin Bj and Bo, Kinnersley and Peters (1928) in their next paper 

 adopted the term yeast vitamin Bi (curative) in place of torulin to 

 designate their yeast concentrate. In this paper they reported attempts 

 to purify and concentrate further the fraction obtained by extracting 

 activated charcoal with tenth-normal hydrochloric acid. Although they 

 were able in one case to concentrate ten- fold about 30 per cent of 

 the vitamin of a preparation of activity of 0.9 milligram by further 

 adsorption at pH 7 with norite, yet in general the relations of the 

 highly active fractions to charcoal could not be defined with certainty, 

 inasmuch as further treatment with norite removed no more vitamin. 

 They concluded that adsorption upon norite in the earlier stages is 

 due to the presence of a co-adsorbent, and considered it preferable 

 to depend upon alcohol fractionation rather than upon successive ad- 

 sorptions to give reproducible results to an activity of 0.15 to 0.3 milli- 

 gram per day. In order to eliminate the large losses during the 

 subsequent alcohol fractionations the tenth-normal hydrochloric acid 

 extracts must first be freed of all traces of metals, and of sulfuric acid 



