r|';tko(;ki-:ssi\-k Tissuii chancics. 243 



EXCESSIVE PIGMENTATION. 



( 1 lyperchromatosis.) 



DEFINITION. 

 ETIOLOGY OR SOVRCE. 

 Hematogenous- 



Hemoglobin. 



Heiiiosideriii. 



Hematoidin. 

 Hepatogenous. 



Bilirubin. 



Biliveridin. 

 Cellular. 



Suprarenal — Addison 's disease. 



Tumoi — Melanin. 



Pregnancy. 



Freckles. 

 E.vtraneous. 



Pneumonokoniosis. 



Anthracosis — Carbon. 



Siderosis — Iron. 



Chalicosis — Lime. 



Kalinosis — Clay. 



Argvriasis — Silz'cr. 

 TATTOO. 

 EFFECTS. 



Excessive pigmentatinn, also known as pigmcntarv infiltra- 

 tion, is a pathologic condition characterized hv tlie presence of 

 an excess of pigment in the tissues. Pathologic pigmentation is 

 quite common. Icterus, melanosis, and anthracosis are tvpes 

 of pathologic pigmentation. This condition ma\- be congenital 

 as melanosis maculosa of calves, or it ma-\' be acquired as in 

 icterus. 



Etiology. — In pathologic pigmentation the coloring matter 

 may be derived from internal sources, as blood, bi'tc and cells, or 

 from external sources as coal dust. sik'Cr. lead and various pig- 

 ments. 



Blood. — Pigmentation as a result of deposition of hemoglobin 

 of the blood is designated hematogenous pigmentation. Hemo- 

 globin is the principal hematogenous pigment, although hemo- 

 siderin and hematoidin, both derivatives of hemoglobin, are of 

 some importance. 



Hcmoqlohin is the normal coloring matter of the red blood 

 cells and muscle. It constitutes about 9(l per cent of the solids 

 of red blood cells. It is a compound proteid and exists onlv in 

 combinalion with lechithin. Plemoglobin splits up readily into 



