THE MICROSCOPE IN PATHOLOGY AND MEDICINE. 229 



lungs ; amyloid matter seeks first the kidneys, next the 

 spleen, liver, etc. In addition, there may be local causes, 

 as pigment deposits from hypereemia, hemorrhage, etc. 



(1.) Amyloid infiltration of tissues. This is a waxy, 

 lardaceous, or vitreous albuminate, but may be distin-" 

 guished from fibrin, albumen, etc., by becoming blue, 

 violet, or red, with iodine. Sometimes it has concentric 

 layers. Its likeness to starch led Virchow to call it 

 amyloid. 



Deposits of fibrin in blood extravasations in the lungs 

 show a change into amyloid, round, small heaps of blood- 

 globules, fragments of tissue, particles of charcoal, etc. 



An amyloid infiltrated cell is larger than natural, and 

 deformed, often coalescing with others. 



The small arteries and capillaries, as the Malpighian 

 tufts of the kidney, etc., are generally the first to suffer 

 infiltration, which extends to the outer coat and surround- 

 ing tissue of the artery, even obliterating it. The degen- 

 eration of vessels leads to anaemia, as in lardaceous liver. 



(2.) Calcification is the infiltration of tissue with solid 

 phosphate and carbonate of lime. Free carbonic acid is 

 the solvent of these salts, and by its capacity for diffusion 

 it escapes, leaving the insoluble salts in the stagnating 

 nutritive fluid. Thus cartilage becomes bone, and under 

 peculiar circumstances other tissues calcify, as the pleu- 

 ritic false membrane, etc. 



(8.) Pigmentation. Under necrosis we referred to col- 

 oring matter of the blood impregnating tissues in soluble 

 form ; under this head we refer to it in solid form, as 

 granules or particles, often without much depreciation of 

 the functions of a part. The color of bile is derived from 

 blood, and jaundice is an infiltration of fluid pigment from 

 absorption of bile color. The black pigment of the lungs 

 is from charcoal or inhaled carbon. Amoeboid cells or 

 leucocytes may imbibe solid particles and carry them in 

 their wanderings. 



