“Some facts showing that the brain educts termed phrenosin (1874) and cerebron (1900) were practically the same”

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 rejoinder some opinions to the contrary.² Reëxamination of the facts in the case have convinced the writer that Thudichum's phrenosin, 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 hydrolysis 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 interchangeable. Each is empirically an approximate multiple of C₈H₁₇O. 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 cerebron were the same: