On so-called " Protagon 



299 



supposed decomposing influence of alcohol by limiting the time of heating 

 during recrystallisation to one minute. 



We give the following experiment in detail ; it is perfectly typical of 

 several we have performed. 



" Protagon " was prepared from ox-brain, following scrupulously Wilson 

 and Cramer's directions. The greatest care was taken to limit the time 

 of extracti(m with hot alcohol to one and a half minutes, and the time of 

 heating during recrystallisation to one minute. The extracts and solutions 

 were cooled at once on ioe. An insoluble residue remained in the first and 

 second recrystallisation, very little in the third and fourth. The following 

 , analjrtical figures were obtained : — 



rt will be seen from these results that the phosphorus percentage of 

 " protagon " falls during four recrystallisations from 1-33 per cent, to 039 

 per cent., notwithstanding the strictest adherence to Wilson and Cramer's 

 conditions. 



From the final phosphorus-poor product we obtained easily by recrystal- 

 lisation from glacial acetic a<Jid (Koch), or by a slight modification of 

 Thudichum's method, a substance which agrees in all its properties with 

 Thudichum's phrenosin ( = Gamgee'8 " pseudocerebrin " and Thier- 

 f elder's "cerebron ") and which is free from phopphofus and sulphur. 



We give below the results of a complete analysis of this substance in 

 order to show the striking differences from the composition of the original 

 " protagon '.' : — 



Phrenosin (our analysis) 



Protagon (Wilson and Cramer's analysis, sample D) 



The results obtained in the recrystallisation of protagon from alcohol, 

 which agree with those recently published by Gies and Cohen,^ are in 

 direct contradiction to those of Wilson and Cramer, who maintain that 

 the phosphorus percentage of " protagon " remains constant, although they 

 obtain the relatively low figure of 092 per cent, after the fourth recrystal- 

 lisation. (The phosphorus percentage of their original " protagon " is not 

 given.) 



' Proc. Soc. Exper. Biol, and Med., vol. v., 1908, p. 97. 



