CHAPTER XV. 

 URINE. 



URINE is the most important excretion of the animal organism; it 

 is the means of eliminating the nitrogenous metabolic products, also 

 the water and the soluble mineral substances; and in many cases it 

 furnishes important data relative to the metabolism, quantitatively 

 by its variation, and qualitatively by the appearance of foreign bodies 

 in the excretion. Moreover, in many cases we are able from the chemical 

 or morphological constituents which the urine abstracts from the kidneys, 

 ureter, bladder, and urethra to judge of the condition of these organs; and 

 lastly urinary analysis affords an excellent means of deciding the question 

 as to how certain medicinal agents or other foreign substances intro- 

 duced into the organism are absorbed and chemically changed. In this 

 respect, urinary analysis has furnished very important particulars especially 

 in regard to the nature of the chemical processes taking place within 

 the organism, and it is therefore not only an important aid to the 

 physician in diagnosis, but it is also of the greatest importance to the 

 toxicologist and the physiological chemist. 



In studying the secretions and excretions the relation must be 

 sought between the chemical structure of the secreting organ and the 

 chemical composition of its secreted products. Investigations with 

 respect to the kidneys and the urine have led to veiy few results from 

 this standpoint. Although the anatomical relation of the kidneys has 

 been carefully studied, their chemical composition has not been the sub- 

 ject of thorough analytical research. In cases in which a chemical 

 investigation of the kidneys has been undertaken, it has been in general 

 only of the organ as such, and not of the different anatomical parts. 

 An enumeration of the chemical constituents of the kidneys known at 

 the present time can, therefore, only have a secondary value. 



In the kidneys we find proteins of different kinds. According to 

 HALLIBURTON the kidneys do not contain any albumin, but only a 

 globulin and a nucleoprotein. The globulin coagulates at about 52 C., 

 and the nucleoprotein contains 0.37 per cent phosphorus. LIEBER- 

 MANN claims that the kidneys contain a lecithalbumin, and he ascribes 

 to this body a special importance in the secretion of acid urines. The 

 kidneys also contain, according to LONNBERG, a mucin-like substance. 



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