CERTAIN DEVITALISED TISSUES- 251 



vitality was thus impaired, always appeared to me 

 necessary to complete the investigation ; and though 

 the researches of Simon, Johnson, Virchow, and 

 others, may have anticipated some of my results, the 

 enumeration of the various effects which I have 

 observed to follow the artificial obstruction of the 

 circulation through the kidney, may yet not be alto- 

 gether useless or uninteresting. 



1. In the majority of cases, after ligature of the 

 renal vein, or renal artery and vein, the kidney be- 

 comes enveloped by a cyst, formed of the surrounding 

 cellular tissue infiltrated with blood and lymph, 

 which cyst is speedily organised and retains the 

 kidney in situ, thus preventing any liquefied portions 

 of the dead organ from escaping into the cavity of 

 the peritoneum. In the interior of this cyst the 

 kidney, deprived of vitality, and no longer nourished 

 by innumerable streams of blood incessantly per- 

 meating its structures, undergoes a process of lique- 

 faction, or softening t which, commencing at the ex- 

 terior, proceeds inwards until the more tenacious 

 central portion is at length also reduced to a pulpy 

 mass. After a period varying in different cases, the 

 kidney is thus wholly converted into a puriform 

 fluid enclosed within the cyst, a pathological con- 

 dition precisely analogous to that which we occa- 

 sionally meet with in the human subject. 



2. But, under certain circumstances, this protecting 

 cyst is not formed, and I have accordingly, after 

 complete obstruction of the renal artery and vein, 

 found the kidney, at the end of twenty-four hours, 

 reduced to a semi-liquid consistency, its pulpy mass 



