URINALYSIS. 137 



sum of the water and urine together. This is not prac- 

 ticable only in case the urine is of high gravity. 



The specific gravity of the urine depends upon the 

 solids in it. The most abundant solid is the urea; the 

 other solids are in the shape of salts therefore, the 

 acids and metals are in the combined state. The tests 

 ior the metals are the same as the ones used in analytical 

 chemistry; this is also true with the acids. The de- 

 composition of urine is accompanied with a peculiar 

 odor, caused by the urea breaking up into its constit- 

 uents. The elimination of the urea represents the tis-- 

 sue metabolism, a process which is explained under the 

 head of Metabolism in this text. The urea represents 

 about two per cent, of the solids, and the solids repre- 

 sent about four per cent, of the urine. "Schroder's ex- 

 periment is as follows : he injected into the liver by the 

 portal vein a mixture of ammonium carbonate and 

 blood, and on examining the blood in the hepatic vein, 

 it was found to contain urea in abundance. This does 

 not occur when the same experiment is performed with 

 any other organ of the body, so that his experiment 

 proves the great importance of the liver in urea for- 

 mation." Kirk. 



The accumulation of urea in the body is called urae- 

 mia, and the same may be said of the accumulation of 

 uric acid ; only the term is uricacidaemia. There is 



