PRINCIPLES OF VETERINARY SURGERY 



535 



was compressed^ softened and reduced to two-fifths of its 

 normal size. Similar tumors have been found in the sacral 

 region, in the liver and in the endocardium. It has been 

 shown in a number of cases that the animals myy die of 

 cachexia in consequence of the generalization of these tu- 

 mors. This form of melanosis is of the rarest kind. It is as 

 rare as the tumors which serve as the substratum for the de- 

 posit of the melanic substance. 



Fig- S9. 

 Melano-Sarcomata of the Heart. (M. Blanc.) 

 V, V, Ventricles. 

 T, T, T, Melanotic Tumors. 



Simple Melanosis. — In simple melanosis the accumulation 

 occurs without presenting any of the characters of true tu- 

 mors. The accumulation of the pigment is the essential pro- 

 cess. The masses have variable dimensions, from those of 

 microscopic particles to volume of the fist, the head, etc. 



The action of the melanic substance on the tissue varies : 

 I St. The pigmentary granules accumulate in the pre-exist- 

 ing tissues, and infiltrate and bury their cells, without des- 

 troying them. The process is one of simple melanic ob- 



