the Urine in Man and Carnivorous Animals, 459 



submitted it to distillation with dilute sulphuric acid, hydro- 

 chloric acid, and oxalic acid ; I obtained so much acetic acid 

 as to be able to prepare with it many ounces of acetate of lead ; 

 from the salt of lead thus formed I was able to produce acetic 

 aether and concentrated acetic acid, which, by mere agitation 

 with tether, lost all urinous odour. Over and above all these 

 tests, the salt of silver formed by this acid was subjected to 

 analysis ; it had crystallized like the common acetate of silver, 

 in shining scales, of easy solution in hot water. 



0*4319 grm. of this salt of silver yielded 0*2808 grm. of 

 metallic silver. 



0'9375 grm. yielded 0*4737 of carbonic acid, and 0*1508 

 of water. 



According to this analysis it consists of, — 



Found. Calculated. 



Carbon . . 13*89 14*49 



Hydrogen . 1*78 1*78 



Oxygen . . 19*32 19*24 



Silver . . . 65*01 64*49 



and this agrees perfectly with the known composition of ace- 

 tate of silver. 



With respect to the presence of acetic acid in putrid urine, 

 this was positively proved by Proust, in a paper published 

 about twenty-four years ago*, and has subsequently been con- 

 firmed by Thenard. This paper of Proust, as well as all the 

 facts and experiments mentioned in it, seems to have escaped 

 altogether the attention of those chemists who have been sub- 

 sequently engaged in investigating the composition of urine. 

 What I have to add to and correct in these works is, in part, 

 contained in Proust's paper. 



Thus, for instance, Proust observed that in the distillation 

 of urine with sulphuric acid or hydrochloric acid, a certain 

 amount of benzoic acid passes over together with acetic acid, 

 and is deposited in crystals in the neck of the retort. I have 

 found that, upon saturating with oxide of lead the acetic acid 

 obtained in this process, a considerable amount of a white pre- 

 cipitate is formed, consisting of pure benzoate of lead. More- 

 over, if the concentrated putrid urine is mixed with some sul- 

 phuric acid, and allowed to stand at rest for the space of se- 

 veral days, a quantity of benzoic acid is obtained in shining 

 brown scales; none of the various urines submitted to these 

 experiments were free from this acid. 



03544 grm. of the benzoic acid produced from urine 

 yielded upon combustion 0*8805 of carbonic acid and 0*1618 

 of water. This gives in 100 parts — 



* Annales de Chiviie et de Pht/sique, vOl. xiv. p. 260. 



