42 CONDITIONS OF INFILTEATION, 



an extent, that no question can arise as to the identity of parts in 

 their unaltered and in their altered state ; cells can still be recog- 

 nised as cells, vessels as vessels, &c. In harmony with this is 

 the fact, that they never entirely lose their physiological capacity, 

 though in this respect the greatest differences exist ; for while 

 amyloid and calcareous deposits are associated with an impair- 

 ment of functional power of the most extreme kind (amounting 

 in some cases to a '' vita minima "), pigmentary and fatty infil- 

 tration are borne with comparative ease. It cannot, however, 

 be denied that a definite impairment of functional capacity, pro- 

 ])ortionate to the degree of the alteration, occurs in all cases, 

 and this obliges us to reckon them among the retrograde pro- 

 cesses. 



All the members of the group have one leading feature in 

 common — the abstraction of certain materials from the blood, 

 and their deposition in the tissues. While other constituents of 

 tlie nutrient fluid pass the cells and other structural elements by, 

 without leaving any trace of their presence, these matters are 

 retained, as the deposit is retained upon a filter. One of the 

 main conditions of this phenomenon is an abnormal accumulation 

 of the morbid material in the blood. 



In many cases, therefore, there is a simultaneous or antece- 

 dent change in the composition of the circulating fluid, a dys- 

 crasia, which manifests its presence, apart from the clinical 

 phenomena of the constitutional disorder, by causing the ana- 

 tomical lesions in question in the most various parts of the 

 organism. This association with a dyscrasic condition of the 

 blood may l)e recognised even in the histological details of the 

 process ; for the singular circumstance that the minute arteries 

 and capillary vessels are the first to undergo infiltration does not 

 admit, in my opinion, of being otherwise explained. It is 

 here that the centrifugal current of nutrient fluid traverses the 

 walls of the circulatory apparatus ; and should the plasma san- 

 guinis be loaded with a substance prone to become deposited in 

 cells, connective tissues, and homogeneous membranes, the sub- 

 stance in question will have its first chance of being deposited, in 

 the parietal elements of this section of the vascular apparatus. 



Besides the antecedent dyscrasia, a great part in the etiology 

 of these infiltrations is played by the local predisposition, the 

 special state, and the individual peculiarities of the several tissues. 



