210 Retrogressive Processes. 



form of brown or black patches, as similarly colored papillary 

 hypertrophies in the pigmented moles (nsevi), freckles (ephelides), 

 liver spots (chloasmata), lentigo; and is also met in increased 

 pigmentation of the cardiac muscle, of the enteric musculature 

 and in a special type of cutaneous pigmentation occurring in a 

 general disease (Morbus Addisonii). In some of the domestic 

 animals the congenital, brown, lentiginous spots are, according 

 to Schindelka, quite common ; the condition known as melanosis 

 maculosa in calves is especially frequent, such an excess of pig- 

 ment cells existing congenitally that spots of inky blackness may 

 be found in large numbers beneath the skin, between the muscles, 

 beneath the pleura and in the lungs, in the epicardium, in the 

 liver, in the submucosa of various mucous membranes and in the 

 membranes of the central nervous system. In foci of local over- 

 production there may often be observed in sheep an excess of 

 the black pigment in the pia mater. There is also seen in calves 

 and in adult cattle rather frequently a sepia-brown to ebony 

 black color of the kidneys, which, from the studies of L. Roth, 

 may be considered due to an infiltration of the epithelium of 

 the convoluted tubules and Henle's loops (the thicker limb) with 

 pigment granules which, in some cases, were identified as melanin, 

 in others as biliverdin. Unquestionably the pigment of melanomata 

 or melanosarcomata (cf. Tumors) is produced by metabolic ac- 

 tivity ; the proliferating cells contain within the protoplasm brown 

 and black granules in thickest profusion. According to the in- 

 vestigations of Berdez and Nenski the coloring matter of the 

 melanotic tumors is rich in sulphur; it is known as hippomclanin 

 and phymatorhasin. 



Haematogenous Pigmentation, Hcemochromatosis. — The color- 

 ing matter of the blood, haemoglobin, in all conditions causing 

 haemolysis or destruction and washing out of red blood cor- 

 puscles, becomes freed from the cells ; and is partly distributed 

 in solution throughout the fluids and tissues, and may be in part 

 precipitated, as is indicated by the pigmentation of the tissues. 

 In the event of large numbers of red corpuscles undergoing 

 solution (haemolysis) within the blood passages, as in various 

 intoxications and infections (blood poisons, piroplasmosis), the 

 coloring matter (haemoglobin or methsemoglobin) is transferred 

 to the blood plasma. The blood becomes lake-tinged, and the 

 serum obtained after venesection from the clot is stained, instead 

 of limpid and yellowish, a deep red (hcemoglobinmnia). The 



