62 On the Action of Potash upon Cholesterine. 



with athal and cholesterine. I then also stated, that although a 

 boiling solution of an alkali might not react upon cholesterine, 

 still I had no doubt that the alkali by itself, aided with a high 

 temperature, would react upon it in a manner similar to that which 

 it did upon spermaceti. From the kindness of M. Pelouze, who 

 famished me with a small quantity of cholesterine, I have been 

 able to examine into the truth of this supposition. 



The first circumstance necessary to be observed in the exam- 

 ination of this reaction, is to have the cholesterine intimately in 

 contact with the potash, and this is done by rubbing together 

 equal parts of the two substances in a mortar. The mixture was 

 placed in a watch-glass, and spread out so as to expose a large 

 surface to the air, the watch-glass was placed on a support in a 

 copper vessel, (the air contained in this vessel could be brought 

 to any required temperature ;) the experiment being thus disposed, 

 the vessel was heated, and by the time that the air in the inte- 

 rior arrived at 248° Fah. a change began to take place in the 

 mixture, and at 266° Fah. it was of a dark brown color. 



This was now treated with cold ether, which dissolved the 

 unaltered cholesterine, and also a matter of a resinous character, 

 which when dissolved in alcohol, and the alcohol allowed to 

 evaporate spontaneously, is deposited in the form of little round 

 concretions entirely devoid of crystalline structure ; it is not solu- 

 ble in any of the alkalies. What remains after the treatment by 

 ether, is of a brown color, and completely soluble in water. If 

 hydrochloric acid be added to this solution, it is decomposed, and 

 a yellowish substance arises to the surface. This substance is 

 soluble in ether, alcohol, potash, soda, and ammonia, as well as 

 their carbonates; it does not crystallize, its alcoholic solution 

 reacts slightly acid upon litmus paper. In fact it is an acid of a 

 resinous character; its combinations with alkalies have the char- 

 acter of soaps. Its silver salt is of a yellow color, but soon be- 

 comes black by exposure to the light. 



From the small quantity of cholesterine that was at my dis- 

 position, 1 have not been able to obtain sufficient of the acid 

 to examine its composition, but I have no doubt that it is a 

 new one. 



If the mixture when heated be not well exposed to the air, 

 very little of this acid is formed, even if we elevate the tempera- 

 ture as high as 300° Fah. ; but on the contrary, a considerable 



