16 



night ; with a flesh diet ; after strong muscular exertion ; during^ 

 the intervals of gastric digestion ; after the ingestion of mineral 

 acids. 



There is increased acidity, pathologically, in fevers ; in rheu- 

 matism ; after asthmatic attacks ; in emphysema, pneumonia 

 and pleuritis. 



The urine is less acid, or alkaline, physiologically, during 

 gastric digestion ; after hot or prolonged cold baths ; after pro- 

 fuse sweating; after copious ingestion of vegetable acids and 

 their salts. 



Pathologically in acute and chronic inflammation of the- 

 urinary tract as in cystitis ; in decomposition of the urine in the 

 bladder in retention ; in some cerebral and nervous diseases ; in 

 anemia ; chlorosis ; and general debility. 



When the urine of man is set aside in a cool place it grad- 

 ually becomes more acid. This is called acid fermentation.. 

 After longer exposure to a warm atmosphere the urine becomes 

 neutral, and finally strongly alkaline in reaction. It becomes 

 turbid, has an ammoniacal odor, and deposits triple phosphate, 

 ammonium urate, and great numbers of microbes exist. This is 

 alkaline fermentation and is due to the transformation of the 

 urea into ammonia and carbon dioxide, by means of a ferment 

 produced by an organism known as the micrococcus ureae. (Fig. 

 20). This organism is said to be conveyed through the air and 

 to exist commonly around the orifice of the urethra. As long 

 as the urine is acid the organism does not exist in the bladder, 

 but may sometimes gain entrance through the medium of a 

 sound or catheter. 



Test the reaction of the urines with red and blue 



litmus paper. Some urines change both the red and 



blue paper and are termed amphoteric. (In taking notes 



of the experiments it is well to record the results in 



parallel columns, the horse urine in one column and the 



human urine in the other). ^ 



Specific Gravity. The specific gravity of human urine 



ranges from 1015 to 1025, the average being 1018 to 1020. That 



of the horse ranges from 1020 to 1050, the average being about 



1035. That of the cow is lower, ranging from 1015 to 1045. It 



seems to depend considerably upon the milk secreted. In milch 



