VITAMIN B (B^) 39 



combustion analyses of the two picrates gave results which agreed 

 closely and corresponded to the formula C6Hi802N3-OH-C6H2(N02)3. 

 In commenting upon the difference in activity of the two picrates, Sei- 

 dell expressed the opinion that the crystalline picrate obtained by 

 Suzuki et al. was the inactive form of the present investigation, but 

 containing a small amount of the active form as an impurity. 



Peters (1924) used the vegetable charcoal "norite" as an adsor- 

 bent of the antineuritic vitamin from an extract prepared from the 

 Osborne- Wakeman yeast concentrate. He first freed this extract of 

 much inactive material by precipitating with neutral lead acetate, acid 

 mercuric sulfate, and barium sulfide, clearing the extract of sulfides, 

 neutralizing it exactly, and making it just acid with acetic acid. To 

 the amount of extract thus obtained from 7 pounds of fresh yeast, 

 30 grams of norite was added. After thorough stirring and standing 

 for 30 minutes the charcoal was separated in a Biichner funnel and 

 washed thoroughly with distilled water. The washings, if colored, 

 were treated with 20 grams of norite, which was then combined with 

 that previously used. The active material was set free from the norite 

 by heating for half an hour on the water bath with 300 cubic centime- 

 ters of 50 per cent alcohol containing 1 cubic centimeter of concen- 

 trated hydrochloric acid per 100 cubic centimeters and repeating the 

 process twice with 150 cubic centimeters of the alcohol. The extract, 

 after concentration to about 20 cubic centimeters by evaporation at 

 a temperature not exceeding 60° C, was still very active and the 

 activity was not destroyed by drying at 100° C. If the hydrochloric 

 acid was not removed the dried material retained its activity for several 

 months at room temperature. 



In testing the activity of his preparations, Peters adopted the earlier 

 curative tests with polyneuritic pigeons, giving as his reason for not 

 using the weight or growth test as employed by Seidell the objection 

 that such tests assume the identity of the curative and growth-promot- 

 ing substances ; and, for not using tests involving the protection of 

 pigeons from symptoms of polyneuritis while upon a polished rice diet, 

 the difficulties raised by the variability of the times of onset of con- 

 vulsions of different pigeons placed upon the same diet. The condi- 

 tions considered by him to be essential in the curative test are as 

 follows : 



"Only those pigeons should be used for the test which show well- 

 marked head retraction, in which the symptoms have appeared within 

 30 to 35 days, and which appear strong enough to withstand treat- 

 ment. If the symptoms clear up completely upon administration of the 



