ABNORMAL CONSTITUENTS OF THE URINE. 403 



Gases. The urine also contains free CO 2 , N, and some O. 100 

 volumes of gas pumped out of fresh urine have been found to 

 consist of 



CO 2 = 65.40 per cent. 

 N = 31.86 " 

 O =*= 2.74 " 



ABNORMAL CONSTITUENTS. 



Different kinds of substances occur in urine under circumstances 

 of special physiological interest, and therefore may be here enu- 

 merated, although their accurate study belongs rather to pathol- 

 ogy. First amongst these to be named is 



Albumin, which occurs from (1) any great increase in the blood- 

 pressure in the renal vessels, whether caused by increased inflow 

 or impeded outflow. (2.) Excess of albumin in the blood, and, 

 strange to say, some forms of albumin escape much more readily 

 than others. Thus egg albumin, globulin, or peptone, if intro- 

 duced artificially into the blood, is soon found in the urine. 

 (3.) A watery condition of the blood, such as would give rise 

 to oedema elsewhere. (4.) Total abstinence from NaCl for some 

 time. (5.) Extensive destruction of the epithelium of the urinary 

 tubes. 



Next in importance to albumin are the following : 



Grape sugar; of which normally only the merest trace occurs 

 in the urine although there is always a certain quantity in the 

 blood. It is present in large quantities in (1) the disease known 

 as diabetes, when a great quantity of pale urine with a very high 

 specific gravity is passed. (2.) After injury of a certain part of 

 the floor of the fourth ventricle of the brain. (3.) After poisoning 

 by curara, carbonic oxide, and nitrate of amyl. In short any 

 disturbance of the circulation of the liver gives rise to an increase 

 of sugar in the blood, and when the amount reaches 6 per cent. 

 it appears in the urine. 



Bile Acids and Pigments appear in the urine when, from occlu- 

 sion of the bile ducts, they find their way into the blood. 



Leucin and Tyrosin also occur in the urine, but only after pro- 

 found interference with the function of the liver. 



