7G E. J. STIEGLITZ 



of urea, all of Sollmann's series are inhibitors of colloidal adsorp- 

 tion of water. Therein probably lies the explanation of the sim- 

 ilarity of the water-secretion curve, with its initial transient rise 

 and later fall, to that obtained with the ferric iron injections. 



In summarizing the results of these investigations concerning 

 ferrocyanide, the essential points to be emphasized are: 1) The 

 diffuse distribution of this salt in distinction from the conspicu- 

 ous tendency toward intracellular localization of ferric iron; 

 2) the probable responsibility of the complex ferrocyanide ion for 

 this diffusion; 3) the prolongation of the period of elimination, 

 resulting from the first characteristic; 4) the relation of those 

 substances stimulating sodium chloride excretion to those 

 inhibiting colloidal hydration; 5) the peculiar susceptibility of 

 sodium thiocyanate to become bound to albuminoid bodies. 



Series V 



The literature on nephritis is as voluminous as that on normal 

 renal secretion. In this paper we will not attempt to broach the 

 subject of pathologic renal function. However, through the 

 means of experimentally produced renal lesions we are able to 

 obtain a clearer insight into the normal physiologic processes. 

 The great variation in susceptibility of the cells of the different 

 units of the uriniferous tubules makes this possible. The col- 

 lecting tubules are much more immune to injurious agents than 

 the secreting tubules (35), as one would expect the much more 

 highly specialized, differentiated cells to be far less resistant. 

 Pearce (31) makes the following excellent generalizations: 

 "The fundamental problem of experimental nephritis is the 

 influence of the glomerulus as contrasted with the influence of 

 the tubule." "The dual structure of the kidney is responsible 

 for the difficulty which we have in interpreting the physiology 

 as well as the pathology of this organ." 



Clinically, the essential classification of nephritis is into acute 

 and chronic forms. The latter are very difficult to produce 

 experimentally, as the acute lesions tend to heal and return to 

 normal, particularly if the cause is no longer active. Lohlein, 



