URINALYSIS. 



The analysis of the urine is very important to the 

 physician and surgeon. It consists of three depart- 

 ments, viz. : chemical, physical and microscopical. In 

 order to gain any information from an analysis, it is 

 necessary to understand the secretion of the urine. 

 There are two theories as to the secretion of it, viz. : 

 the capsule of Bowman, acting as a filter, separates 

 the urine from the blood ; the epithelial cells lining the 

 uriniferous tubules secrete a part of the urine. In 

 fact, both processes go on at the same time. The first 

 is Ludwig's theory, and the second is Bowman's. The 

 experiment of Heidenhain settled the question of the 

 epithelial cells having a part in the secretion of the 

 urine. He injected a coloring matter into the veins of 

 an animal. After a suitable time he made sections of 

 the kidneys of the animal, and found the coloring mat- 

 ter in the cells of the uriniferous tubules, but none in 

 the capsule of Bowman. Other experiments prove the 

 theory good, for when a patient has uremia, the urinif- 

 erous tubules have lost their epithelial lining, as shown 

 by the microscope on analyzing the urine. The theory 



of Lurwig is proven by the change in the amount of 



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