

155 



it as a combination of phosphate of potash and a pure organic sub- 

 stance. The filtered fluid, after separation of this matter, still con- 

 tains a substance which he has called Excretolic acid. It is obtained 

 by evaporating to dryness, extracting the residue with ether, adding 

 to the ethereal solution alcohol and lime-water, and heating. The 

 acid is precipitated in combination with lime, from which it is sepa- 

 rated by means of sulphuric or hydrochloric acid and solution in 

 ether. The ethereal solution, after being well washed with water 

 to remove mineral acid, yields the pure excretolic acid on evapora- 

 tion. This body is of an olive colour; it fuses between 25 and 

 26 C., and at a higher temperature burns without residue. It is 

 insoluble in water and in a boiling solution of potash ; very soluble 

 in ether, sparingly soluble in cold alcohol, readily so in hot; its 

 solutions having a marked acid reaction. The author is disposed to 

 believe that in excrement it is combined in form of a salt, with ex- 

 cretine or a basic substance closely allied to it, which is obtained in 

 the filtrate from which the excretolic acid is precipitated in com- 

 bination with lime in the process of its purification. 



The author failed to obtain evidence of the presence either of 

 butyric or of lactic acid in the clear alcoholic solution of faeces filtered 

 from the precipitate formed by the milk of lime. From the above 

 investigation, therefore, it appears that healthy human excrements 

 contain : 



1 . A new organic substance, possessing an alkaline reaction, which 

 the author names Excretine. 



2. A fatty acid, having the properties of margaric acid, but not 

 constantly present. 



3. A colouring matter, similar to that of blood and urine. 



4. A light granular substance, whose properties have not yet 

 been sufficiently examined to admit of its being considered a pure 

 substance. 



5. An acid olive-coloured substance, of a fatty nature, named 

 Excretolic acid. 



6. No butyric acid and no lactic acid. 



The faeces of various animals were submitted to the same process 

 of analysis, with the following results : 



1. The excrements of carnivorous mammalia, viz. the Tiger, Leo- 

 pard and Dog (fed on meat), contain a substance allied in its na- 



VOL. VII. Q 



