198 THE JOURNAL OF PHARMACOLOGY. 



in the form of an acid salt, but in urine of acid reaction a certain amount of 

 Di-Sodic hydric phosphate (NA 2 HP0 4 ) alkaline in reaction, may be found. 

 If the latter salt be present in certain quantity a peculiar condition pre- 

 vails, that is, such a sample of urine will redden blue litmus paper, and 

 cause red paper to turn blue ; such a reaction is known as an amphotor re- 

 action. Urine having a neutral reaction is never found ; neither does free 

 acid occur in urine. Normal urine may react alkaline ; such is often the 

 case during the process of digestion, when much acid is secreted, or it may 

 prevail when the urine contains an unusual quantity of bases, viz., Carbon- 

 ates after ingestion of such, or ingestion of certain organic substances, 

 examples, Citrates and Tartrates, which in the body are converted into 

 Carbonates. 



Pathologically the urine may become alkaline from the reabsorption of 

 alkaline transudates, or after an intestinal hemorrhage (here from the ab- 

 sorption of alkaline salts of the blood), etc., etc. 



Appearance. — Normal acid urine is voided clear and transparent, as 

 all the acid and normal salts present in such urine, are soluble in water, 

 and only in such cases where the quantity of water becomes lessened so 

 that it can no longer keep the salts in solution, notably the acid urates, 

 does the urine, although acid in reaction, become turbid. This occurs 

 mostly after elimination, but may occur before. 



Normal alkaline urine is usually voided turbid, because the salts present, 

 viz., alkaline phosphates, and carbonates of the alkali earths, are in- 

 soluble, or only sparingly so, in water. 



Even transparent and clear urine does not contain all its constituents in 

 true solution. Such traces of albumens as may be present are only held 

 in suspension. This accounts for the fact that urine passes through a 

 filter with decreasing rapidity ; at times filtration is even brought to a 

 standstill. 



Fresh acid urine contains normally a few epithelial cells and a small 

 quantity of mucus. 



Specific Gravity. — This normally may be stated as about 1.018, although 

 under normal conditions it may fluctuate widely, viz., 1. 002-1. 030. Such 

 variation depends chiefly on the quantity and quality of the ingested 

 solids and liquids and the rapidity with which tissue changes in the body 

 go on. Active muscular exercise favors tissue waste, and consequently in- 

 creased elimination of nitrogenous material results, with an attendant rise 

 in specific gravity. Profuse diaphoresis, either as the result of food ingested 

 or of exercise, cause a rise in the gravity because the aqueous constituent is 

 lessened and the urine thereby concentrated. Conversely, if large quan- 

 tities of water be ingested a lower specific gravity prevails. Patholog- 

 ically the gravity may be raised or lowered ; thus certain diseases, notably 

 Glycosuria, are accompanied by a urine of high gravity, while others, 

 again, show a decided decrease in the gravity. Wherever the specific 

 gravity becomes lowered and the volume of urine remains normal it is 



