PIGMENTARY INFILTRATION. 283 



These minute refractive granules enlarge and extend, and so 

 form dark, opaque, granular patches white, grayish, or yel- 

 low in color rnacroscopically. Physiologically the condition 

 occurs in the pineal gland, choroid plexus, in cartilage in old 

 age, and notably in the development of bone. The most 

 frequent pathological sites are the valves of the heart, arterial 

 walls, caseous lymph-glands, and in myoma uteri when the 

 blood-supply is poor. It may be noted in necrotic tubercular 

 foci and infarcts. 



Pigmentary infiltration, or abnormal pigmentations, depend 

 on both intrinsic and extrinsic sources of supply, the former 

 being either hsematogenous or non-hsematogenous. 



1. Intrinsic: a. Hsematogenous. There are tw r o varieties 

 of pigment derived from haemoglobin when red blood-cells are 

 destroyed : hsemosiderin, which contains iron, and hsematoidin, 

 which does not. 



Hsemosiderin gives the characteristic chemical reactions 

 of iron, and occurs in minute granules in the liver-cells in 



FIG. 117. 



Pigmentation of the lung (from a woman, set. sixty-five, with slight emphysema), 

 showing the situation of the pigment in the thickened alveolar walls and around 

 the bloodvessel, v. The walls of the latter are also thickened and its lumen 

 diminished. X 75 (Green). 



pernicious ana?mia; and is found also in the spleen, renal 

 epithelium, and medulla of bone in this disease, in leuka?mia, 

 malaria, severe cachexias, in poisons, and septic processes. 



