101 



precipitated in the secretion of the urine, for want 

 4>f a sufficient quantity of acid to dissolve it. The 

 urea, which my predecessors had described, I 

 found to be a composition of the urea, properly 

 so called, and several deliquescent substances, 

 which they had not succeeded in separating from 

 it. The urea, such as I obtained it in my expe- 

 riments, is void of colour, and forms very distinct 

 prismatic crystals like nitre. It is, however, 

 very obstinately combined with lactic acid, lac- 

 tate of ammonia, ^and the above mentioned ani- 

 mal matter, which always accompanies this acid 

 and its salts, and which probably is also always 

 formed at the same time with them. This ani- 

 mal matter has a brownish yellow colour, and in 

 combination with the lactic acid and its salts 

 gives to the urine its colour. It is easily dis- 

 solved both by alcohol and water, and from this 

 substance, and not from albumen, as was for- 

 merly supposed, arises the precipitate, thrown 

 down from urine by tanning. The matter, which 

 in urine precipitates corrosive sublimate, is not 

 only albumen (the presence of which in case of 

 disease is very probable) but also a peculiar ani- 

 mal matter, which is not dissolved by alcohol, but 

 which, like that soluble in alcohol, always ac- 

 companies the lactic acid and its salts. It is not 



3 



