14 MODE OF PRODUCTION 



walls of, and hence obliterate the cavity naturally 

 existing in the latter, so that the free surface es- 

 sential for secretion no longer occurs; whence in 

 the case of the kidneys, retention of urea in the 

 blood and the not unfrequent occurrence of death as 

 the termination of one of the forms of coma described 

 by Dr. Addison. 



In chronic nephritis a minor degree of congestion 

 exists, for the blood does not enter the renal arteries 

 with so powerful an impulse or in such large quan- 

 tity as in acute inflammation; and hence in the 

 former the relative quantity of albumen in the urine 

 is less. Other causes probably tend also to the same 

 end ; for, in addition to the heart participating in 

 the general debility, as shown by the decreased 

 power and activity of the circulation, the blood as 

 the disease advances contains less albumen than in 

 health ; and being largely composed of water its 

 tenuity favours transudation, and its more aqueous 

 portion escapes in the form of urine of a low specific 

 gravity. When, from the operation of any acci- 

 dental cause, there is an unusual determination to 

 the kidneys, the congestion will naturally be for 

 the time increased, and as an immediate consequence, 

 more albumen will be effused into the urine. But 

 on the other hand, if no unnatural excitement, causing 

 increased action of the renal vessels, take place for a 

 length of time, the latter will become accommodated 



O * 



to their contents, and the albumen thus lost to the 

 system may be reduced to a very minute quantity, 

 or altogether cease, but will be immediately repro- 

 duced on the recurrence of any increase of vascu- 



