Comparative Anahjsh rf the Urine of various Anlmah. 19 



the beaver, proved ihat it has a great resemblance to the 

 iiraie of the common herbivorous animals. 



In fact, we there find carbonate oFlinifi kept in solution 

 by a superabundance of carbonic acid; benzoic and acetic 

 acids, urea, muriate of soda and sulphate of potash ; and 

 we meet with no uric acid in it, or phosphoric salts. 



Nevertheless it differs in so far as.it contains no muriate 

 of ammonia, and as possessing z considerable quantity of 

 carbonate and acetate of magnesia, which is not found, at 

 leait in a great quantity, in the urine of herbivorous ani- 

 mals. 



I discovered the carbonate of magnesia in the following 

 manner : 



After having concentrated by a gentle beat a certain, 

 quantity of this urine, I decanted the liquor, and washed 

 with distilled water the vessel to the sides of which the 

 carbonate of lime adhered. I afterwards passed sulphuric 

 acid into it diluted v.ith water, which produced a frothy 

 effervescence on account of a raucous matter which carries 

 off" with It the carbonate of lime. 



Pcrceivins that the sulphuric acid had acquired a bitter 

 taste from this combination, I dried and calcined the mix- 

 ture, then I washed it with a little water, and I obtained by 

 the evaporation of the latter, a salt which had ail the pro- 

 perties of sulphate of magnesia. 



Wishing to ascertain by another experiment, if there was 

 muiiate of ammonia in the urine of the beaver, as well as 

 in that of other herbivorous animals, 1 put into a portion 

 of this tbickertd liquor a piece of caustic potash ; and as 

 the odour of the ammonia was not perceived even with 

 the aid of heat, I concluded that it did not contain any 

 muriate of ammonia: but a phaenomenon was exhibited 

 which astonished nie, and which excited a desire to ex- 

 amine the cause of it. The liquor went into a gelatinous- 

 like mass : suspecting that this effect wai produced by the 

 precipitation of some carihv substance, I treated the whole 

 of the thickened urine which I possessed with caustic 

 potash ; I filteicd the liquor in order to obtain the matter 

 in question ; and after having washed and calcined it, I 

 combmcd it with' sulphuric acid diluted with water, and 

 obtained sulphate of magnesia mixed with a little sulphate 

 of lime. 



Although I have announced that the urine of the beaver 

 contains acetate of magnesia, yet I am not perkctly cer- 

 tain of it: in (act, it may be possitjle that durinii the eva- 

 poration, although effected witti a gentle heat, a cortani 



B 2 quantity 



