72 ANIMAL ACIDS CONTAINING AZOTE. 

 SECTION XVI. OF OLEOPHOSPHORIC ACID. 



The presence of this acid in the human brain, and doubtless 

 in that of the inferior animals, has been lately discovered by M. 

 Fremy. * 



It has been stated in the preceding section, that when the ethe- 

 rial product of the brain is treated with ether, there remains in 

 solution a viscid substance which contains oleophosphoric acid, 

 frequently combined with soda. To obtain the acid we must de- 

 compose this salt with an acid, and digest the mass in boiling 

 alcohol, which dissolves the oleophosphoric acid, and lets it pre- 

 cipitate as it cools. Thus obtained it is always mixed with olein, 

 which may be removed by anhydrous alcohol. We may free 

 it from cholesterin, which is often present, by alcohol and ether, 

 which dissolve the cholesterin more readily than the oleophos- 

 phoric acid. It has not yet, however, been obtained in a state 

 of purity. Fremy was not able to free it completely from cho- 

 lesterin and eerebric acid. 



It has usually a yellow colour, like olein. It is insoluble in 

 water, and swells a little when put into boiling water. It is al- 

 ways viscid. In cold alcohol it is insoluble, but dissolves rea- 

 dily in that liquid when at the boiling temperature. It is soluble 

 in ether. 



When placed in contact with potash, soda, or ammonia, it im- 

 mediately forms soapy compounds similar to the matter extract- 

 ed from brain when treated with ether. With the other bases 

 it forms compounds insoluble in water. When oleophosphoric 

 acid is burnt in the open air, it leaves a strongly acid charcoal, 

 in which the presence of phosphoric acid may be detected. 



When this acid is boiled for a long time in water or alcohol, 

 it gradually loses its viscidity, and is changed into a fluid oil, 

 which possesses the characters of pure olein. The water or al- 

 cohol holds a notable quantity of phosphoric acid in solution. 

 This decomposition is very slow and incomplete when the oleo- 

 phosphoric acid is treated with pure water or alcohol, but be- 

 comes very rapid when these liquids are rendered slightly acid. 

 It takes place at the common temperature, but very slowly. The 

 atmosphere has no share whatever in this decomposition. 



Olein is soluble in absolute alcohol, but oleophosphoric acid is 

 quite insoluble in that liquid. This shows that oleophosphorie 



* Jour, de Pharm., xxvii. 463. 



