PBOTAGON. 57 



accurately determined ; viz., protagon, neurine, fatty matters 

 combined with phosphorus, and bases combined with peculiar 

 fatty acids. 



Protagon. This principle was discovered by Liebreich, 

 and described in 1865. 1 Its formula is C 116 H 341 O 3a ]Sr 4 P. It 

 may be extracted by the following process : The cerebral 

 substance is bruised in a mortar, and afterward shaken with 

 water and ether in a closed vessel. The mixture is then ex- 

 posed to a temperature of 32 Fahr., and the ethereal layer, 

 containing cholesterine, is removed. The insoluble mass is 

 then extracted with alcohol, 85 per cent., at 113, is again 

 filtered and exposed to a temperature of 32. An abundant 

 precipitate then separates, which is washed with ether and 

 desiccated in vacuo. The protagon is thus obtained in the 

 form of a white powder. Since this principle has been de- 

 scribed in the brain-substance, a compound analogous to, if 

 not identical with protagon, has been discovered by Her- 

 mann in the blood-corpuscles. 5 In its general and chemical 

 characters, protagon resembles the albuminoid proximate 

 principles ; but it presents the remarkable difference, that 

 the sulphur, which exists in many of the principles of this 

 class, is replaced by phosphorus. 



. This name has been applied to a rather indefi- 

 nite principle supposed to represent the albuminoid element 

 of the nervous tissue ; but its characters as a proximate con- 

 stituent of the nerve-substance have never been well deter- 

 mined. Robin and Yerdeil place neurine among the proxi- 

 mate principles of probable existence. According to these 

 authors, this is the organic substance of the brain, not soluble 



1 LIEBREICH, Ueber die chemische Beschaffenheit der Gehimsiibstanz. Annalen 

 der Chemie und Pharmacie, Leipzig und Heidelberg, 1865, Bd. cxxxiv., S. 29, 

 (t seq. 



8 HERMANN*, Ueber das Vorlcommen von Protagon im Blute. Archiv fur 

 pathologische Anatomic und Physiologic, Berlin, 1866, S. 36, ft seq. 



