y6 (246) Society for Experimental Biology and Medicine. 



49 (141). " Some facts showing that the brain educts termed 

 phrenosin (1874) and cerebron (1900) were practically the 

 same " : WILLIAM J. GlES. 



In a discussion of the chemical heterogeneity of protagon, the 

 author previously alluded to the probability that phrenosin and 

 cerebron were identical. 1 Thierfelder recently published in re- 

 joinder some opinions to the contrary. 2 Reexamination of the 

 facts in the case have convinced the writer that Thudichum's phren- 

 osin, Gamgee's pseudocerebrin, Parcus's cerebrin, Kossel and 

 Freytag's cerebrin, Thierfelder's cerebron and Koch's cerebrin 

 were practically the same. The slight discrepancies among the 

 figures for percentage elementary composition were probably due 

 to slight proportions of inevitable impurities in each preparation. 



Of the products referred to, phrenosin and cerebron have been 

 subjected to the most thorough study. The descriptions of each 

 are in close harmony. Each has been found to yield, on hydroly- 

 sis with dilute sulfuric acid, apparently the same proportions of a 

 sugar (galactose), a nitrogenous base (sphingosin) and a peculiar 

 organic acid. The following data were obtained on direct analysis 

 of the latter product : 



If the inevitable impurities in each product are disregarded it 

 seems obvious that the names refer to the same substance. 

 The following formulas were assigned to it : 



It is apparent, however, that the formulas are practically inter- 

 changeable. Each is empirically an approximate multiple of 

 C 8 H 17 0. With this fact in mind the following equations that were 

 given to represents the relations of the cleavage products to the 

 mother substance, emphasize the opinion that phrenosin and cere- 



1 I'osner and Gies : Journal of Biological Chemistry, 1905, i, p. 59. 

 * Thierfelder 1 Zeittchrift fur phytiologische ChemU % 1906, xlvi, p. 51S. 



Neurostearic acid 



(obtained by Thudichum from phrenosin). 

 Cerebronic acid 



(obtained by Thierfelder from cerebron). 



C. H. 

 75.94 12.64 



75-33 12.50 



Thudichum's product (Neurostearic acid) 

 Thierfelder's product (Cerebronic acid)... 



