294 DIGESTION. 



tine contained in the fasces is not very great, as only 12'6 grains were obtained by Marcet 

 from nine evacuations. 



We have very little definite information concerning the production of excretine. 

 Marcet examined, on one occasion, the contents of the small intestine of a man that had 

 died of disease of the heart, without finding any excretine. It is probable that this 

 principle 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 proper- 

 ties. 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 at from 77 to 79 Fahr. 



Stercorine. This principle, which we discovered in the fasces in 1862, was described 

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

 and was called by him seroline. As we found it to be the most abundant and character- 

 istic constituent of the stercoraceous matter, we proposed to call it stercorine; particu- 

 larly as our researches led us to the opinion that it really does not exist in the serum, but 

 is formed from cholesterine by the processes employed for its extraction. 



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 decolorize entirely 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 caustic potash 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 

 is washed until the fluid which passes through is neutral and perfectly clear. The filter is 

 then carefully 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 composed of pure stercorine. 



When first obtained, stercorine is a clear, slightly amber, oily substance, 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, we obtained, from seven 

 and a half ounces of normal human faeces (the entire quantity for the twenty -four hours), 

 10-417 grains of stercorine, the extract consisting of nothing but crystals. This was all 

 the stercorine to be extracted from the regular, daily evacuation of a healthy male 

 twenty-six years of age and weighing about one hundred and sixty pounds. In the ab- 

 sence of other investigations, the daily quantity of this substance excreted may be as- 

 sumed to be not far from ten grains. 



In many regards, stercorine bears a close resemblance to cholesterine. It is neutral, 

 inodorous, and insoluble in water and in a solution of potash. It is soluble in ether and in 

 hot alcohol, but is almost insoluble in cold alcohol. A red color is produced when it is 

 treated with strong sulphuric acid. It may be easily distinguished from cholesterine, 

 however, by the form of its crystals. It fuses at a low temperature, 96'8 Fahr., while 

 cholesterine fuses at 293 Fahr. 



Stercorine crystallizes in the form of thin, delicate needles, frequently mixed with 

 clear, rounded globules, which are probably composed of the same substance in a non- 

 crystalline form. When the crystals are of considerable size, the borders near their ex- 

 tremities are split longitudinally for a short distance. The crystals are frequently ar- 

 ranged in bundles, as in Fig. 81, in which they are represented as seen under a -^-inch 

 objective. In Fig. 82, the crystals are represented as seen under a |-inch objective. 

 These crystals cannot be confounded with excretine, which crystallizes in the form of 



