ki-:t«oc,ki-:ssive tissue changi-:s. 1\7 



The effects of resorption of bile are variable. The tissues are 

 discolored; there ma}^ be pruritus, as the bile appears to act as 

 an irritant on nerve endings; putrefactive chanoes may occur in 

 the intestine, and the heart may be depressed. (Ither inconstant 

 symptoms may appear, especially if the quantity of resorbed 

 bile is large. 



Cells. — Aside from hematogenous, and hepatogenous ]iigmenta- 

 tion the products of certain body cells become a factor in hyper- 

 chromatosis. 



The principal pigment produced by cellular activitv is mel- 

 anin. Alelanosis maculosa is a congenital, cutaneous, patnologic 

 pigmentation of calves resulting from the excessive production 

 of melanin bv cutanet)us cells in certain areas. 



^lelanotic deposits arc of common occurrence in the various 

 glandular tissues, especially the liver, kidney, and suprarenal 

 glands. The deposits in the glandular tissue mav occur in the 

 cells or intercellular spaces, and ma}^ appear as irregular yellow- 

 ish-brown or black masses. Melanin may occur in the form of 

 fine granules or be flocculent. Black kidneys are occasionally 

 observed, in abattr)irs, especially in hogs. These usually result 

 from deposition of delicate, flocculent masses of melanin in the 

 kidnev cells. 



Melanosis is of most frequent occurrence in white animals, 

 although it has been observed in Aberdeen angus cattle, red 

 short horns, black and ba\- horses, and black and red hogs. 



^lelanotic tumrirs are pigmented with melanin. The melanin 

 ma^- be a product of the tumor cells or of the adjacent tissue 

 cells. The principal melanotic tumors are the melano-sarcomata, 

 although there ma's' be a benign melanotic tunidr called a mel- 

 anoma. 



In a disease of the suprarenal capsule in the human (Addi- 

 son's disease) there is a peculiar bronzing of the skin. This con- 

 dition has not been noted in the domestic animal, proliablv be- 

 cause of the dense jiigmentation of the skin. It is thought to be 

 a form of melanosis. 



A pigmentation has been noted in atrophic tissues, especially 

 atrriphied muscles. The pigment cif atroi)hic muscles may be 

 the result of disturbed cell metabolism or it ma\- result from con- 

 centration of the pigment, because of the diminutiim in the size 

 of the cells. Brown atrophy of the heart is a condition in which 

 pigmentation is prominent. 



Freckles are pigmented areas of the skin in the human, the 

 result of cutaneous cellular action. Because of the intense pig- 



