OF THE URINE. 303 



It is a common mistake even at present to ascribe,, as Blumen- 

 bach necessarily did, the colour and smell of urine to the urea, 

 which is now known to be colourless and have an extremely faint, 

 and by no means urinous, smell. Dr. Front has established that 

 urea consists of 



Hydrogen ----- .266 



Carbon ------ .799 



Azote - 1.866 



Oxygen 1.066 



4.000* 



The same physician has procured from lithic acid a curious 

 substance which he denominates the purpuric acid.f 



The urine of birds is generally discharged with the faeces, and 

 becomes solid by exposure to the air. That of serpents is dis- 

 charged only once in some weeks, is of a caseous consistence, 

 and likewise becomes perfectly solid afterwards. Both are nearly 

 pure uric acid.J The urine of the turtle and tortoise is also 

 destitute of urea, but does not contain a great deal of pure uric 

 acid. The analysis of the urine of brutes is highly interesting, 

 but is not yet either extensive or accurate. 



* Med. Chir. Trans. Vol. Lx. 

 f Philos. Trans. 1818. 



J Dr. Prout, Thomson's Annals of Philosophy. Dr. Davy, Philos. Trans. 

 1818. 



