460 LIQUID PARTS OF ANIMALS. 



stances by the concretion of which calculi are produced. He 

 detected also phosphate of lime in urine.* 



In 1808, Berzelius published the second volume of his Ani- 

 mal Chemistry, in which he gives a long account of the proper- 

 ties of urine, and mentions the action of reagents on it, but gives 

 no quantitive analysis. His well-known analysis of urine appear- 

 ed first in his paper entitled General Views of the Composition of 

 Animal Fluids, published in 1813 in the third volume of the Me- 

 dico-Chirurgical Transactions.! 



About ten years after this, I made many experiments on urine, 

 and likewise analyzed this liquid from a healthy individual ; but 

 the paper lay by me unpublished till it was inserted in the second 

 volume of the Records of General Science in 1 835. In 1839, an 

 elaborate paper on the variation of the constituents of urine in 

 the same and in different individuals was given to the public by 

 M. Lecanu.J Of this important paper an abstract will be given 

 in this chapter. 



Urine is secreted by the kidneys and conveyed by the ureters 

 to the bladder, from which it is voided occasionally when its pre- 

 sence gives rise to a feeling of uneasiness. It was generally sup- 

 posed by physiologists that the solid substances which it holds in 

 solution were formed by the action of the kidneys ; but the expe- 

 riments of Prevost and Dumas have made it almost certain that 

 they all exist in the blood, and that the office which the kidney 

 performs is only to separate them from the other constituents 

 with which they are mixed in the blood-vessels. For when they 

 extirpated the kidneys from animals and examined their blood 

 two or three days afterwards, they were able to detect in it 

 a sensible quantity of urea. 



Human urine when newly emitted has a yellow colour, more 

 or less deep, according to circumstances. It is transparent, though 

 sometimes when left at rest in a glass it deposits a few flocks of 

 mucus. It has a distinct aromatic smell, which has been compar- 

 ed to that of violets. When it cools, the aromatic smell leaves 

 it, and is succeeded by another well-known by the name of uri- 

 nous. This odour is in two or three days (when the urine is from 

 young or middle-aged persons) succeeded by another which has 



* Scheele's Essays, p. 199. f Annals of Philosophy, ii. 422. 



t Jour, de Pharmacie, xxv. 681, 746. 



