ITS CHEMICAL CONSTITUTION. 115 



cerebric acid adhering to it. We may, however, readily convince 

 ourselves that Fremy was mistaken in believing free phosphoric 

 acid to be formed, the substance being, as Gobley has found, phos- 

 phate of glycerine. I succeeded on one occasion in most unques- 

 tionably demonstrating the presence of phosphate of glycerine in 

 the mass obtained from a very diffused yellow softening of the 

 brain, which, as Rokitansky has shown, contains a free acid. More- 

 over while Fremy found from 1'9 to 2*0 of phosphoric acid in his 

 oleophosphoric acid, Gobley, on decomposing the same acid by 

 acids and alkalies, always obtained margaric acid in addition to oleic 

 acid, a proof of the obscurity which still envelopes the whole sub- 

 ject. It seems indeed to be proved, from the observations hitherto 

 made in relation to this question, that the elements of these two 

 kinds of cerebral fats are very unstable, that is to say, that 

 they are extremely prone to numerous decompositions, and that 

 they are mere admixtures of substances of which the one may have 

 served the other as a medium of solution or distribution. The 

 presence of nitrogen in the cerebric acid, and Fremy's assertion 

 that albumen passes into the ethereal solution, are questions which, 

 singularly enough, have hitherto failed to excite observers to any 

 more exact investigations, although they are at variance witli pre- 

 existing observations, and may very probably be of great signifi- 

 cance in reference to the function of the nervous system, which is 

 so immutably combined with its chemistry. 



The cholesterin which occurs in the fat of the brain is partly 

 taken up by the alcoholic extracts, and partly dissolved by ether, 

 together with the cerebric and oleophosphoric acids, which it ac- 

 companies in all their solvents. 



The analyses of so careful an observer as Fremy preclude the 

 possibility of doubting that pure olein is contained in brain-fat, 

 although we cannot consider it as demonstrated that this olein 

 is derived from the (so-called) oleophosphoric acid. 



The quantity of oleic and margaric acids obtained by Fremy 

 on extracting the brain-fat with alcohol containing ammonia, 

 is very small. When, as is often the case, these fatty acids are 

 found in considerable quantity in the brain, their presence may 

 in reality be owing to the facility with which the brain and its 

 fats are decomposed. 



We know but little of the chemical composition of the morpho- 

 logical elements of the nerve-cells, for the micro-chemical reactions 

 already given lead us to very few conclusions on this point. From 

 these observations it appears that the investing membrane of these 



12 



