NITROLEtJCIC ACID. JS 



Acid is not a mere mixture of olein and phosphoric acid, but a 

 compound of the two. But after the oleophosphoric acid has 

 been boiled in water or alcohol, the olein being separated from 

 the acid, is readily taken up by absolute alcohol, even without 

 the application of heat. The olein thus disengaged burns upon 

 platinum foil without leaving any residue, which is not the case 

 with oleophosphoric acid. 



From these facts it is obvious that oleophosphoric acid is very 

 easily altered in its nature. Hence the reason why it is frequently 

 found in a brain quite fresh ; though no traces of it can be dis- 

 covered after the brain has been left for some time to putrefy ; 

 but instead of it, much olein and phosphoric acid in a separate 

 state. M. Fremy is of opinion that this tendency to decomposi- 

 tion may account for some of the changes which are apt to take 

 place in a living brain. 



Oleophosphoric acid is readily acted on by fuming nitric acid. 

 Phosphoric acid is dissolved, and a fatty acid swims on the sur- 

 face of the liquid. The quantity of phosphoric acid determined 

 in this way varies from 1'9 to 2 per cent 



The alkalies added in excess transform the oleophosphoric acid 

 into oleates, phosphates, and glycerin. 



Fremy considers oleophosphoric acid to be a compound of 

 phosphoric acid and olein. But he could not succeed in his at- 

 tempts to combine these two bodies artificially. It must be ac- 

 knowledged that such a compound, if it do exist, is of a very sin- 

 gular nature. Olein is a compound of oleic acid and glycerin, 

 in reality a salt, while phosphoric acid is a powerful acid. 



SECTION XVII. OF NITROLEUCIC ACID. 



This acid was discovered by Braconnot in 1820.* When 

 minced animal muscle is digested in water till everything solu- 

 ble is removed, and, after being exposed to pressure, is mixed with 

 its own weight of concentrated sulphuric acid, it swells up and 

 dissolves and a little fatty matter swims on the surface, which 

 must be removed. This mass being mixed with twice its weight 

 of water and boiled for nine hours, taking care to add water as 

 fast as it Evaporates, the muscle undergoes decomposition. Am- 

 monia is formed, which unites with the sulphuric acid, while from 

 the other constituents of the muscle at least three new principles 



* Ann. de Chim. et de Phys. xiii. 118. 



