STERCORIN 233 



water, slightly soluble in cold alcohol, but very soluble in ether and in 

 hot alcohol. Its alcoholic solutions are faintly though distinctly alka- 

 line. Its fusing-point is between 203 and 205 Fahr. (95 and 96 C.). 

 It may be boiled with potassium hydrate for hours without undergoing 

 change. The quantity of excretin contained in the f eces is not large. 

 Only 12.6 grains (0.8 16 gram) were obtained by Marcet from nine 

 evacuations. In 1857 Marcet assigned to excretin the formula 

 C 78 H 78 O 6 ; but the formula C 20 H 36 O is now given in works on physio- 

 logical chemistry. 



There exists little definite information regarding the production of 

 excretin. Marcet examined on one occasion the contents of the small 

 intestine of a man who had died of disease of the heart, without finding 

 any excretin. It is probable that this substance is formed in the large 

 intestine, although further observations are needed on this point. 



The substance called excretoleic acid is indefinite in its composition 

 and properties. It is described as an olive-colored fatty acid, insoluble 

 in water, non-saponifiable and very soluble in ether and in hot alcohol. 

 It fuses between 77 and 79 Fahr. (25 and 26.11 C.), but its existence 

 is doubtful. 



Stercorin. This substance was discovered in the feces in 1862 

 (Flint). As it is one of the most abundant and characteristic constitu- 

 ents of stercoraceous matters, it may properly be called stercorin. Ster- 

 corin may be extracted in the following way : The feces are first 

 evaporated to dryness, pulverized and treated with ether. The ether- 

 extract is then passed through animal charcoal, fresh ether being added 

 until the original quantity of the ether-extract has passed through. It 

 is impossible to entirely decolorize the solution by this process ; but it 

 should pass through perfectly clear and of a pale-amber color. The 

 ether is then evaporated and the residue is extracted with boiling 

 alcohol. The alcoholic solution is evaporated, and the residue is treated 

 with a solution of potassium hydrate for one or two hours at a tempera- 

 ture a little below the boiling-point, by which the fats are dissolved. 

 The mixture is then largely diluted with water, thrown upon a filter 

 and washed until the liquid which passes through is neutral and per- 

 fectly clear. The filter is then dried and the residue is washed out with 

 ether. The ether-solution is then evaporated, extracted with boiling 

 alcohol and the alcoholic solution is evaporated. The residue of this 

 last evaporation is stercorin, which may be purified by recrystallization. 



When first obtained, stercorin is a clear, slightly amber, oily sub- 

 stance, of about the consistence of Canada balsam used in microscopical 

 preparations. In four or five days it begins to show characteristic 

 crystals. These are few in number at first, but soon the entire mass 



