)2 ANIMAL ACIDS CONTAINING AZOTE. 



ployed a dicholeate of lead falls. Both are nearly insoluble in 

 water, but soluble in acetic acid. They have a resinous con- 

 sistence. 



5. Nitrate of silver forms with choleate of soda a white preci- 

 pitate, which by washing is converted into dicholeate of silver. 

 After being dried in vacuo over sulphuric acid, its constituents 

 were, 



Choleic acid, 50*58 



Oxide of silver, 29- 



Now 29 is the weight of two atoms of oxide of silver. Hence 

 the salt is a dicholeate. 



SECTION XIII. OF CHOLESTERIC ACID. 



Cholesterin, a substance having some resemblance to sperma- 

 ceti, and a very frequent ingredient in gall-stones, seems to have 

 been first particularly noticed by Gren in 1788.* In the year 

 1817, the action of nitric acid upon this substance was particu- 

 larly examined by Pelletier and Caventou.f They ascertained 

 that by this action a peculiar acid was formed, to which they 

 gave the name of cholesteric. The subject was again resumed 

 by Pelletier in 1832.} He subjected it to an ultimate analysis 

 and determined its constituents. 



Cholesterin was treated with its own weight of concentrated 

 nitric acid. The acid when assisted by heat speedily dissolved 

 the cholesterin, while at the same time abundance of deutoxide 

 of azote was evolved. When the solution cooled a yellow-co- 

 loured matter separated, and when the liquid swimming over this 

 deposit was diluted with water, an additional portion of the same 

 substance was separated. This yellow substance was not sensi- 

 bly soluble in water ; but on elevating the temperature, it swam 

 like butter upon the surface of the water. When well washed 

 it was deprived of all acid taste ; but had a peculiar though 

 slight stypticity. Yet it was capable of reddening litmus-paper, 

 and of saturating the alkaline bases with considerable energy. 

 To purify the cholesteric acid thus obtained Pelletier and Ca- 

 ventou proceeded in the following manner : A portion of it was 



Diss. contin. duas observations circa calculos, Sfc. Hal. 1788, 62. As 

 quoted by L. Gmelin, Handbuch der Theoretischen Chemie, ii. 504. 

 t Jour, de Pharmacia, iii. 292. 

 { Ann. de Chim. et de Phys. li. 189. 



