CHAPTER XIV. 

 THE URINE. 



THE urine is the most important excretion of the animal or- 

 ganism; it is the means of eliminating the nitrogenized products 

 of exchange, also the water and the soluble mineral substances; 

 and in many cases it furnishes important data relative to the 

 exchange of material ; quantitatively, by its variation, and qualita- 

 tively by the appearance of foreign bodies in the excretion. Also 

 in many cases we are able from the chemical or morphological 

 constituents which the urine abstracts from the kidneys, ureters, 

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

 and lastly, urinary analysis affords an excellent means of deciding 

 the question how certain medicines or other foreign substances 

 introduced into the organism are absorbed and chemically changed. 

 Urinary analysis has furnished very important particulars espe- 

 cially relative to the last-mentioned question in regard to the 

 nature of the chemical processes taking place within the organism, 

 and it is therefore not only an important aid in diagnosis to the 

 physician, but it is also of the greatest importance to the toxicol- 

 ogist and the physiological chemist. 



In studying the secretions and excretions the relationship must 

 be sought between the chemical structure of the secreting organ 

 and the chemical composition of its secreted products. Investiga- 

 tions with respect to the kidneys and the urine have led to very 

 few results from this standpoint. Although the anatomical rela- 

 tion of the kidneys has been carefully studied, their chemical com- 

 position has not been the subject of thorough analytical research. 

 In cases in which a chemical investigation of the kidneys has been 

 undertaken, it has only been in general on the organ as such, and 

 not on the different anatomical parts. An enumeration of the 



330 



