EXCRETION 393 



taking place in the kidney, and upon the general problems of 

 metabolism. Even in health the quantity of the urine, its 

 specific gravity, its acidity, may vary within wide limits. A 

 hot day may increase the secretion of sweat, and correspond- 

 ingly diminish the secretion of urine, and the deficiency of 

 water may lead to a deposit of brick-red urates. A meal 

 rich in fruit or vegetables may render the urine alkaline, and 

 its alkalinity may determine a precipitate of earthy phos- 

 phates. But neither the scanty acid urine, with its sediment 

 of urates, nor the alkaline urine with its sediment of phos- 

 phates, comes under the heading of pathological urines ; 

 the deviation from the normal does not amount to disease. 

 The maximum deviation from the line of health is the total 

 suppression of the urine. If this lasts long, a train of 

 symptoms, of which convulsions may be one of the most 

 prominent, and which are grouped under the name of 

 uraemia, appears. At length the patient becomes comatose, 

 and death closes the scene. Suppression of urine may be 

 the consequence of many pathological conditions, but there 

 is one case on record which, in the human subject, in effect, 

 though not in intention, belongs to experimental physiology. 

 A surgeon diagnosed a floating kidney in a woman. With 

 a natural impatience of loose odds and ends of this sort, he 

 offered to remove it, and in an evil hour the patient con- 

 sented. The surgeon, a perfectly skilful man, who acted for 

 the best, and to whom no blame whatever attached, carried 

 the kidney to a well-known pathologist for examination. 

 The latter, to the horror of the operator, suggested, from 

 the appearance of the organ, that it was the only kidney 

 the woman possessed. This turned out to be the fact. 

 Not a drop of urine was passed. Apart from this ominous 

 symptom, all went well for seven or eight days; but then 

 uraemic troubles came on, and the patient died on the 

 eleventh or thirteenth day after the operation. The autopsy 

 showed that her only kidney had been taken away. 



In disease the urine may contain abnormal constituents, 

 or ordinary constituents in abnormal amounts. Of the 

 normal constituents which may be altered in quantity, the 

 most important are the water, the inorganic salts, the urea, 

 the uric acid, and the aromatic substances. 



