VITAMIN G (B.) 121 



the principle outlined in the preceding paragraph by tests in which the 

 Seidell activated solid (activated fuller's earth) was used as the sole 

 source of vitamin B for rats. When this was fed at a 5 or 6 per cent 

 level, good growth to approximately adult size resulted. When, how- 

 ever, the amount was reduced to between 0.5 and 1 per cent, growth 

 was quickly arrested and the rat declined without evidence of poly- 

 neuritis, but in some cases with the development of symptoms more or 

 less suggestive of pellagra. On adding to the diet 9 per cent of auto- 

 claved yeast or 6 per cent of a fuller's earth preparation activated with 

 autoclaved yeast, growth was resumed with improvement and disap- 

 pearance of the "pellagra-like" condition. This was considered to 

 indicate that in Seidell's activated fuller's earth the limiting factor for 

 growth was the thermostable substance. 



The diet selected by Goldberger and Lillie for their study of the 

 effect of lack of this factor alone upon young rats was the familiar 

 vitamin B-free diet of casein, salt mixture, cod-liver oil, hydrogenated 

 cottonseed oil, and corn starch. To this was added an 85 per cent alco- 

 holic extract of corn meal dried on cornstarch. Such an extract had 

 been shown in their previous work to be rich in the antineuritic vitamin 

 (B) but to contain little of the heat-stable antipellagric factor (now 

 called vitamin G). On the basal diet supplemented by 6 per cent or 

 more of this extract, healthy young rats after some initial growth in- 

 variably lost weight rapidly. An increase in the amount of extract even 

 to 71 per cent of the ration failed to check this decline. In no case were 

 symptoms of polyneuritis noted, but in many of the rats a condition 

 showing considerable similarity to pellagra developed after varying 

 lengths of time (never less than 7 weeks). The symptoms as described 

 included a form of ophthalmia followed closely by a dermatitis, mani- 

 festing itself by a falling out of the fur and dry incrustations of the 

 skin. Other symptoms characteristic of pellagra were occasionally noted, 

 including ulceration at the angles of the mouth, inflammation of the 

 anterior part of the floor of the mouth, and diarrhea. All of these symp- 

 toms if taken in time disappeared promptly upon the addition of 6 per 

 cent of fuller's earth activated by autoclaved yeast. Goldberger and 

 Lillie, although convinced of the similarity of this condition with human 

 pellagra, were of the opinion that additional evidence is required to 

 establish it beyond reasonable doubt. 



Meanwhile Laird (1926), in McCollum's laboratory, found in the 

 testing of numerous extracts obtained from natural foods by means of 

 different (usually acidulated) solvents, many instances in which the 

 antineuritic and growth-promoting potencies did not run parallel, and 



