TUMORS. 



,i07 



in relation with periosteum. They frequently contain cartilag- 

 inous, osseous or calcareous centres. 



jMicroscopically, they are composed of myeloid cells and 

 round or spindle cells. The myeloid cells are the distinguishing 

 elements of this variety of sarcoma. The size of the myeluid 

 cells is variable, frecjuently being 80 to 100 microns in diameter 

 and with an irregular outline, varying in shape from a sphere to 

 an elongated mass. Their protoplasm may be quite granular or 

 almost clear. They have manv nuclei — 150 being observed in 

 one cell. These nuclei have no definite arrangement but occur 

 miscellaneouslv throughout the entire cell body. The r(jund and 

 spindle cells are like those occurring in round and spindle-cell 



Fig. 162.- 



-Photograph ot horse's head affecti'd with mix 



■ d eell Saro(nna. 



sarcoma. There mav be an excess of one or the other or they 

 may be equal in number. The intercellular su1)stance vanes 

 from mucoid to calcareous in nature. There is usually an exces- 

 sive blood supply, the blood vessel walls being usually normal 



