338 COLLOIDS IN BIOLOGY AND MEDICINE 



Pathology of Urine Secretion. 



As our preceding statements show, two different functions of the 

 kidney may suffer: the nitration of the glomeruli and the concen- 

 trating activity of the tubules. 



Filtration is deficient whenever the glomerular filter is damaged; 

 it will also be abnormal if there is nothing to be filtered, which 

 happens when an insufficient quantity of arterial blood containing 

 free water is supplied to the glomeruli. 



MARTIN H. FISCHER ** finds the chief cause of nephritis is an ab- 

 normal increase in the acidity of the kidney cells. It is the cause of 

 albuminuria. According to him, the acid dissolves kidney protein 

 so that the urine contains albumin; it dissolves away the formed 

 elements (epithelial cells), which are then washed into the urine as 

 casts. Depending upon the (experimental) conditions, epithelial, 

 granular or hyaline casts are formed. "The first change to the 

 second, and these to the third variety if the acid concentration is 

 progressively increased. Hyaline may be changed back to granular 

 casts if a little salt is added to the acid solution." (M. H. FISCHER.) 

 M. H. FISCHER supports this theory with numerous experiments. 



The increase in acidity may result from a deficient supply of oxygen 

 to the kidneys which may be due to a number of different causes. 

 It may be caused by deficient cardiac activity of any kind, hemor- 

 rhages or irritation of the vasomotor nerves, as well as compression 

 of the renal artery by a tumor, or interference with the flow of blood 

 resulting from arteriosclerosis or embolism. Congestion of the renal 

 vein must of course have a similar effect. [Lack of exercise with 

 insufficient breathing may induce acidosis. Tr.] 



Disturbances of renal function may result directly or indirectly 

 as a result of toxic influences, such as chemical poisons and toxins 

 from infections. In such case the oxidation processes of the renal 

 cells suffer so that renal edema results, and this causes a compression 

 of the blood vessels, so that the supply of arterial blood to the kidneys 

 is deficient; a vicious circle is thus established. 



M. H. FISCHER also explains the action of alcohol and anesthetics 

 in a very plausible way. Small doses increase the excretion of 

 urine by increasing and strengthening the heart's action, and the 

 respiratory frequency by vasodilatation; these are all factors which 

 favor the supply of oxygen to the blood, and in that way the 

 formation of free filterable water. Caffein and digitalis act in a 

 similar way., Large doses of alcohol, ether, chloroform, chloral, mor- 

 phine, etc., on the contrary, bring about a deficiency of oxygen, 

 causing a binding of water by the body colloids and thus a diminu- 

 tion of the secreted urine (see E. FREY). 



