RETROGRESSIVE TISSUE CHANCES. 245 



blood cells. Hemoglobin pigmentation, the results of bruising, 

 is common in the superficial tissues of animals slaughtered im- 

 mediately after shipping. 



Hciuosidcnu is a derivative of hemoglobin. It is j^ellowish 

 brown in color, is insoluble in water, alcohol, ether, chloroform. 

 dilute acids and alkalies. It contains iron and gives the typical 

 iron reaction with potassium ferrocyanid. Hemosiderin is ihe 

 common pigment observed in tissues that have been previously 

 stained with hemoglobin. E.xtra\'asated blood observed in pete- 

 chiae and hematomata appear as typical hemoglobin pigmenta- 

 tion for a few days, after which the hemoglobin is ci)n\-erted into 

 hemosiderin and the affected parts become a j'clliiwish brown. 

 Hemosiderin pigmentation is observed in tissues of animals that 

 have been bruised three or four days prior to slaughter. It is 

 also observed in post-mortem examinations of animals that have 

 been affected with diseases accompanied by hemorrhages for a 

 period of three to five days, as purpura hemorrhagica, acute tick 

 fever, anthrax, etc. Hemosiderin pigmentation is of common 

 occurrence in tumors. 



Hciiiatoidiu is an iron free pigment, probably derived from 

 hemosiderin. It is soluble in chloroform, but is insoluble in 

 water, alcohol and ether. It occurs in rhombic crystals and is 

 occasionally observed in old hemorrhagic foci. 



Blood pigments, hemoglobin, hemosiderin, and hematoidin 

 are deposited in the cells and intercellular substances. The pig- 

 ments are removed by solution and resorption of the dissolved 

 pigment or bv leucocytes which incorporate the insoluble pig- 

 ment granules and carry them out. 



Blood pigmentation has little eft'ect upon the tissue in which 

 deposition occurs, but the flesh of food producing animals is 

 usually condemned when pigmeated because of its unsightly 

 appearance. 



The deposition of a brownish or blackish pigment in bones 

 (ochronosis) is occasionally observed in the carcasses of cattle 

 which were apparently in good health. The cause of this pig- 

 mentation is unknown. It probably does not injure the tissues 

 or the meat for food, but such meats are usually condenmed be- 

 cause of their unsightly appearance. Another brownish pig- 

 mentation of muscular tissue (xanthosis) is associated with mus- 

 cular atrophy or disease of the suprarenal bodies. This condi- 

 tion is of no' consequence except public sentiment prevents the 

 sale of such meat. 



Bile pigmentation results from the resorption of bile and its 



