AMYLOID INFILTRATION. 47 



those capillary loops only, wliicli do not present the characteristic 

 homogeneous and glassy appearance. The addition of iodine 

 produces an exquisite alternation of red and blue loops in the 

 rete mirabile. 



^ 49. In this degeneration of the vessels, we find the prin- 

 cipal cause of those abnormalities which amyloid organs exhibit 

 to the naked eye. 



The most marked of these is the comparative bloodless- 

 ness of the organs. This anaemia is not due solely to the 

 closure of the vessels by swelling of their walls ; it is partly 

 accounted for by the greater relative space occupied by the 

 degenerated as compared with the normal parenchyma, and the 

 consequent compression of the vessels ; that this is so, is proved 

 by the case of amyloid infiltration of the liver. In this organ 

 the amyloid matter is chiefly deposited, not in the capillary walls, 

 but in the hepatic cells which lie between them ; and yet the 

 ana[?mic condition of the waxy liver is as distinct as possible. 



The less the colour of an organ depends on the blood which 

 it contains, the more apparent is the special colour of the organ 

 itself. This is especially true of organs which have undergone 

 amyloid degeneration ; in them we see the peculiar colour and 

 quality (Beschafienheit) of the amyloid matter asserting itself in 

 proportion to the degree of the infiltration. The parts assume a 

 pale yellow or clear grey tint ; they become as soft as wax, the 

 pressure of the finger leaving a persistent mark. When the 

 •degeneration is absolutely complete (a very rare phenomenon, 

 which has hitherto been observed only in parts of the thyroid 

 gland and the spleen), the comparison with white wax, proposed 

 by Virchoio, is most appropriate. 



^ 50. The form of amyloid degeneration described above 

 commonly follows prolonged suppuration in bone, caries of yqv- 

 tebrse, necrosis, &c. ; it is not unfrequently associated, moreover, 

 with constitutional syphilis, more rarely with pulmonary tuber- 

 culosis and other cachexia3 ; all cases in which a pre-existent 

 dyscrasia of the blood may be unconditionally assumed as its 

 basis. 



I have only a few words to add with reference to the local 

 occurrence of amyloid matter. Allusion has already been made 

 to the laminated concretions found in ha^morrhagic deposits in 

 the lungs. We saw that fibrin, after lying for sonic 



