THE URINE. 333 



what extent any one acid takes part in the acid reaction; but as the 

 .sum of the base equivalents is greater than, or at least the same as, the 

 sum of the inorganic acid equivalents, the acid reaction must be 

 due in greatest part to organic acids or acid salts. It is generally 

 considered that the acid reaction of human urine is caused by 

 double-acid alkali-phosphate (monophosphate). The amount of 

 acid-reacting bodies or combinations eliminated by the urine in 24 

 hours, when calculated as oxalic acid or hydrochloric acid, is re- 

 spectively 2-4 and 1.15-2.3 grms. (VOGEL). 



The composition of the food is not the only influence which 

 affects the degree of acidity of human urine. For example, after 

 taking food, at the beginning of digestion, when a larger amount of 

 gastric juice containing hydrochloric acid is secreted, the urine may 

 be neutral or even alkaline. The greatest amount of acid or acid- 

 salts per hour is secreted, according to VOGEL, during the night, 

 while according to HOFFMANN, it is in the afternoon. The smallest 

 amount is voided, according to HOFFMANN during the night, but 

 QUINCKE claims that it is in the morning. It has not infrequently 

 been observed that perfectly healthy persons in the morning void a 

 neutral or alkaline urine which is cloudy from earthy phosphates. 

 The effect of muscular activity on the acidity of urine is yet 

 undetermined. According to HOFFMANN and EINGSTEDT, mus- 

 cular work raises the degree of acidity, but ADUCCO claims that it 

 decreases it. Abundant perspiration reduces the acidity (HOFF- 

 MANN). 



In man and carnivora it seems that the degree of acidity of 

 the urine cannot be increased above a certain point, even though 

 mineral acids or organic acids which are burnt up with difficulty 

 are taken in large quantities. When the supply of carbonates of 

 the fixed alkalies stored up in the organism for this purpose is not 

 sufficient to combine with the excess of acid, then ammonia is split 

 from the proteids or their decomposition products, and the excess 

 of acid combines therewith, forming ammonium-salts which pass 

 into the urine. In herbivora this splitting of ammonia and forma- 

 tion of ammonia-salts does not seem to take place, and the herbiv- 

 ora therefore soon die when acids are given. Nevertheless, the 

 degree of acidity of human urine may be easily diminished so that 

 the reaction is neutral or alkaline. This occurs after the taking of 



