CONTENTS OF THE LARGE INTESTINE. 265 



with the microscope, these are found to consist of acicular, four-sided prisms 

 of variable size. Excretine is insoluble in water, slightly soluble in cold alco- 

 hol, but very soluble in ether and in hot alcohol. Its alcoholic solutions are 

 faintly though distinctly alkaline. Its fusing-point is between 203 and 205 

 Fahr. (95 and 96 C.). It may be boiled with potassium hydrate for hours 

 without undergoing saponification. The quantity of excretine contained in 

 the faeces is not large. Only 12-6 grains (0-810 gramme) were obtained by 

 Marcet from nine evacuations. 



There exists very little definite information concerning the production 

 of excretine. 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 

 excretine. It is probable that this substance is formed in the large intestine, 

 although farther observations are wanting on this point. 



The substance called excretoleic acid is very 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.). 



Stercorine. This substance, discovered in the faeces in 1862 (Flint), was 

 described by Boudet in 1833, as existing in minute quantity in the serum of 

 the blood, and was called seroline. As it is one of the most abundant and 

 characteristic constituents of the stercoraceous matter, it may properly be 

 called stercorine, particularly as observations have led to the opinion that 

 it really does not exist in the serum, but is formed from cholesterine by the 

 processes employed for its extraction from the blood (Flint). 



Stercorine may be extracted in the following way : The faeces 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. This alcoholic solution is 

 evaporated, and the residue is treated with a solution of potassium hydrate 

 for one or two hours at a temperature a little below the boiling-point, by 

 which all the saponifiable fats are dissolved. The mixture is then largely 

 diluted with water, thrown upon a filter, and washed until the fluid which 

 passes through is neutral and perfectly 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 pure stercorine. 



When first obtained, stercorine is a clear, slightly amber, oily substance, of 

 about the consistence of Canada balsam used in microscopical preparations. 

 In four or five days it begins to show the characteristic crystals. These are 

 few in number at first, but soon the entire mass assumes a crystalline form. 

 In one analysis, from seven and a half ounces (202-5 grammes) of normal 

 human faeces (the entire quantity for the twenty-four hours), 10-417 grains 

 (0-675 gramme) of stercorine were obtained, the extract consisting entirely 



