S43 Analysis of the Cerehral Matter of Man, [May, 



caustic potash, and during the solution no ammonia is disen^ 

 gaged, as is the case with the curdy portion of milk when 

 dissolved in the same raauner. 



The solution of this substance in potash is slightly brown, its 

 smell is nqt strong, the acids precipitate it in the form of white 

 flocks, an4 disengage a very fetid odqur. When acetate of lead 

 is dropped into the solution, a dark brown precipitate falls^ show- 

 ing ojbviously the presence of sulphur. 



Five grammes (77-2 grains troy) of this matter cautiously 

 distiUed, fuj-nished carbonate of ammonia in crystals, and a red 

 oil haying a smell similar to that of albumen decomposed in the 

 same manner. There remained in the retort 1 gramine (15-4 \ 

 grains troy) of charcoal, which required 5 grammes of nitre to 

 be entirely burnt. 



The solution of salt obtained from it left 5 centigrammes 

 (0*77 of a grain troy) of earthy residue, which was phosphate of 

 lime. The liquid being supersaturated by nitric acid, and 

 subjected to ebullition, let fall np precipitate ; but it yielded a 

 copious one when rnixed with lime-water. This shows that the 

 phosphate of magnesia h^d been decomposed by the potash, and 

 perhaps even a portion of the phosphate of lime. 



This matter heated alone in a crucible, decrepitates, swells, 

 and melts like albumen. Its charcoal, though calcined for a 

 long time, does not become acid like that of the fatty matter ; 

 which shows that it contains no phosphorus. This charcoal, 

 being washed with muriatic acid, furnished a small quantity of 

 phosphate of lime and phosphate of magnesia. 



When tlirown into melted nitre it burns rapidly, and with 

 flame ; and we find in the alkali vesulting from that operation 

 very sensibly? traces pf sulphuric acid, though the saltpetre 

 employed contained none of it. This proves that the matter of 

 the bmin which '-^ insoluble in alcohol contains sulphur; and 

 confirms what was indicated by the acetate of lead dropped into 

 the alkaline spluiion of this substance. 



The properties, which the portion of the brain insoluble in 

 alcphol has presented, leave no doubt that it is perfectly identical 

 with albumen. The knowledge of thi^ circumstance esiplain? 

 very well the coagulation pf th^ brain mixed with water by 

 heat, acj(ls, metallic salts, &c. This was the opinion v/hich 

 Fourcroy had formed of this substance in his memoir oi^ the 

 subject published in the Annales de Chimie, 



Sect. IX. 



General Result, 



The mass of the brain^ then, is composed the following 

 substances:— 



