528 PRINCIPLES OF VETERINARY SURGERY" 



In a melano-sarcoma of man, an analogous substance 

 richer in sulphur, and called phymatorusine is found. 



Knowing its physico-chemic characters and origin, the 

 localizations may then be considered. 



ORIGIN. — The origin of a melanotic pigmentation has 

 been the subject of considerable discussion. According to 

 Breschet, it is of a hsemorrhagic nature ; the blood poured 

 out becomes decomposed and provokes pigmentation by the 

 transformation of hasmatin in melanin. According to other 

 writers, melanin results from alterations in the coloring 

 matter of the blood, while still others opine that the patho- 

 logical black pigment is elaborated by the cell, because it 

 may appear at some distance from the blood vessels. 



Heurtaux, endeavoring to reconcile the various theories, 

 says : "If the hsematin furnishes the elements of the pig- 

 me,nt, it is certainly not owing to an infiltration of a san- 

 guineous nature, and an alteration caused by extravasation 

 of the corpuscles among the elements of the tissue. The au- 

 thors who believe in the haematic origin of the pigment have 

 not maintained that the blood poured out is directly con- 

 verted into melanin. They simply intended to say that 

 its materials have been borrowed from the blood, and espec- 

 ially from its coloring matter." In favor of this theory it 

 is pointed out that in melanaemia a great number of san- 

 guineous elements contain particles of pigment, especially 

 haematin, which leads to the formation of a pigmentary em- 

 boli. On the other hand, it has been discovered by Bruck- 

 muller that in two horses suffering from melano-sarcomato- 

 sis, there were similar lesions which imparted a deep brown 

 color to the blood. A like phenomenon in a calf was observed 

 by Bollinger. It might, of course, be contended that the 

 melanotic granules might have been carried into the blood 

 by the leucocytes. 



The process of pigmentation is the same in the 



