THE URINARY ORGANS. 637 



inflammatory processes not* infrequently supervene in kidneys which are 

 the seat of slowly developed chronic processes ; so that lesions typical of 

 both acute and chronic nephritis are not infrequently associated. Finally 

 it is evident that the grouping of the kidneys in chronic diffuse nephritis 

 in accordance with the structural elements of the organ most conspicu- 

 ously involved is essentially artificial, since this in many cases is simply 

 an indication of the period of the disease at which the patient died. 



The Excitants of Chronic Diffuse Nephritis. The conditions under which 

 chronic diffuse nephritis occurs are most diverse. Thus, judging from 

 the clinical history, it may be a primary process ; it may follow infec- 

 tious diseases either with or without a previous acute nephritis ; it is not 

 infrequently associated with gout and syphilis, with lead poisoning, with 

 excessive use of alcohol, with arteriosclerosis, with general chronic con- 

 gestion of the viscera, with chronic 



suppurative and tuberculous processes, <=-' c " r " *^' 



and appears in many cases to develop .,$ " ~- ~~i-^ -^ ^ 



under the influence of dietetic excesses ,-'^L' -^ ~' -- *"* >*v 

 and protracted gastro-intestinal dis- ,^ // / ; v ;^vr\ v= 

 orders. The nature of the excitants '^j ' ' ', f j( : L^----" V V V 

 under these various conditions is most ./ . , * ' ' 



obscure. Although in gout, lead poison- f^' ^ 

 ing, alcoholism, etc., a fairly definite ' V' * 

 inciting toxic agency may be assumed, " 

 the exact mode of action of such ex- 

 trinsic or intrinsic poisons is almost .. ... 



wholly unknown. In regard to other 



excitants of chronic diffuse nephritis, ^njJ 



the prevalent views as to the impor- WITH CH&ONIC DIFFUSE NEPHRITIS. 



tance of disturbed metabolism in the 



body which may lead to the excretion of abnormal harmful products 



favor the conjecture that in many cases at least both the degenerative 



and the productive processes may be the marks of a persistent auto- 



intoxication. 



The relationship between arterio- sclerosis and chronic kidney lesions 

 is not clear. Nor is it certain, assuming the initial importance of ob- 

 structive vascular lesions, whether the new formation of fibrous tissue 

 should be regarded as a primary productive inflammation or as replace- 

 ment hyperplasia secondary to epithelial degeneration and tubular 

 atrophy. 



It should be remembered that in most cases the lesions of chronic 

 diffuse nephritis are not independent, but are usually associated with 

 those of other viscera. The significance of this association varies greatly. 

 While the kidney lesions may be primary they are very often secondary 

 to other visceral abnormalities, or the whole series of lesions may be de- 

 pendent upon a common known or unknown etiological factor. 1 



1 For studies bearing on experimental nephritis see Castaigne and Rathony, Sem. 

 Med., September 23d, 1903. Also TJtorel, D. Arch. f. kl. Med., Bd. Ixxvii., 1903. 



