414 



3. The fact that vegetable food induces the presence of margaric 

 acid in excrements has heen confirmed. 



4. The existence of a comparatively large quantity of cholesterine 

 in the spleen, which I had mentioned before as probable, has been 

 confirmed. 



When human faeces are exhausted with boiling alcohol, the fluid 

 being rapidly strained through a cloth, a clear extract is obtained, 

 which, on cooling, yields a deposit ; this substance, being collected 

 on a filter, is partly soluble in boiling alcohol, and there remains un- 

 dissolved a residue insoluble in ether and alcohol. The residue in 

 question being boiled with a solution of potash, dissolves almost 

 entirely, and the addition of hydrochloric acid induces the formation 

 of a precipitate in the solution. On examining this precipitate, it 

 was found to consist of a crystallizable substance fusing at 60 Cent. ; 

 its structure and other properties were precisely those of margaric 

 acid. 



The acid filtrate contained phosphoric acid and lime. From 

 several quantitative analyses, I concluded that there was more lime 

 than is required to combine with the phosphoric acid in the form of 

 the neutral phosphate, the excess of lime being exactly that which 

 was necessary to convert the margaric acid into a neutral margarate 

 of lime, C^HgjjOg + CaO. Consequently it followed that the three 

 substances existed in the form of margarate of lime and phosphate 

 of lime as immediate principles of human faeces. 



The alcoholic filtrate from the deposit being allowed to stand for 

 twenty-four hours, deposited another substance, of a nearly white 

 appearance, and which proved to be margarate of magnesia. 



The peculiar action of a vegetable diet on human faeces was inves- 

 tigated by means of experiments undertaken upon myself, when I 

 observed that an entirely vegetable diet was attended with the form- 

 ation of a large quantity of margaric acid in the excrements, most 

 probably not in the form of a margarate, but in the free state, inas- 

 much as it was obtained from the decomposition, with hydrochloric 

 acid, of the precipitate induced by adding milk of lime to the cold 

 and clear alcoholic extract of faeces, after the separation of the above- 

 described deposits. 



In the month of December 1855, I had an opportunity of noticing 

 that during a cold night, when the temperature falls below the 



