tHi On the Benzoic Acid in the Urine of Horses. 



experiments ; but these conducted me to phjenomena whick 

 inouced me to proceed further than I had at first purposed. 



Experiment I. 



To two pounds of fresh horse's urine I added muri- 

 atic acid the specific gravity of which was as 115 to 

 100. A weak effervescence took place, and there were 

 formed thick white vapours, which soon fell to the bottom 

 like flakes. I now continued to add muriatic acid till no- 

 thing more was separated, and till there remained a gniall 

 excess, three ounces of acid having been employed. The 

 •whole was then placed on a filter; and the precipitate, being 

 vashed with pure water to free it from the urine still ad- 

 hering to it, was then dried. It amounted in weight to two 

 drams and forty-eight grains. On being subjected to a 

 proper test, it evidently exhibited all the properties by which 

 the benzoic acid is characterized ; namely, a scarcely sour- 

 ish taste, crystallization, complete volatility, the disengage- 

 ment of an acrid vapour, which occasioned pain in the breast, 

 and ready solution in spirit of wine. 



Paving fully convinced myself by this experiment of the 

 ^undant ejiisteiice of benzoic acid in urine, I continued 

 »iy researches on the urine of more horses, partly with i, 

 view of observing the difference of the proportions in itj, 

 and partly to ascertain whether something determinate 

 ^ight not be established on this subject. 



Experiment II. 



YoMT pounds of urine were svrbjected to the same treat- 

 jnent as before. The phaenomena were here different frorni 

 those of the first experiment ; for, on adding muriatic acid, 

 no precipitate was produced. When the fluid was evapo- 

 rated to a fourth, and after the fluid had stood at rest for 

 jome time, I observed a small and resin-like precipitate, 

 which, after being treated with spirit of wine, gave benzoic 

 acid, but in so small a quantity that it bore no proportion 

 t6 that of the first cxperniient, for it amounted only to five 

 grains. 



Expeiiment III. 



Eight pourids of horse's nrine being evaporated to the 

 consistence of syrup, muriatic acid was then added ; but 

 no precipitation ensued. The fluid was then brought to 

 complete dryness ; and spirit of wine being poured over it, 

 when it had Scood some time the undissolved residuum was 

 separated by the filter, and the liquor evaporated. I ob- 

 iained a very small quantity of crystallized benzoic acid, 

 3 whichi 



