4 8o 



EXCRETION 



constituents, especially the chlorine, since sodium chloride is quanti- 

 tatively the most important of the salts. Various formulae have been 

 deduced from such determinations connecting the freezing-point and 



conductivity with other physical constants of the urine. E.g., - = 

 K=75, where s is the specific gravity and K a constant with the value 

 75. The quotient -^ ^y representing the ratio of the total concen- 

 tration to the sodium chloride concentration, varies within relatively 

 narrow limits in health, according to Koranyi, the diet exercising no 

 influence upon it whatever. Thus, in a large number of healthy 



individuals XT rl fluctuated only between 1*23 and 1-69, while A varied 



JN clv^l 



from 1-26 to 2'35, and the percentage of sodium chloride from 0-85 

 to 1-54. This is illustrated in the table: 



The Urine in Disease. Although, strictly speaking, a truly patho- 

 logical urine has no place in physiology, the line which separates the 

 urine of health from that of disease is often narrow, sometimes invisible ; 

 while the study of abnormal constituents is not only of great importance 

 in practical medicine, but throws light upon the physiological processes 

 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 correspondingly 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 phosphates. But neither the 

 scanty acid urine with its sediment of urates, nor the alkaline urine 

 with its sediment of phosphates, comes into the category 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 con- 

 vulsions 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 in the human subject which, 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 

 consented. The surgeon, a perfectly skilful man, who acted for the 



