TUMORS. 



301 



are not growing rapidl}'. The portion of the cell body not occu- 

 pied by the nucleus is composed of undiiierentiated protoplasm. 

 In appearance the intercellular suljstance varies according to 

 its composition. An abundance of capillaries and small blood 

 vessels are found in sarcomata. These may be normal in struc- 

 ture or they may be infiltrated with sarcomatous tissue, and, 

 in some cases, the blood flows througli channels formed bv sar- 

 coma cells. Hemorrhage is of frecjuent occurrence in sarcomata. 

 The blood vessels have no regularitv in their distribution, a 

 structural jieculiaritv frequentU- resulting in degeneration and 

 necrosis. Lymphatic spaces and vessels are absent in sarcomata, 

 excepting lympho-sarcomata, unless they are entangled during 

 the development of the tumor. Nervous tissue has n<it Ijeen 

 demonstrated as a distinct entitv in sarcomata. There are usu- 

 allv many leucocytes and frequently some plasma cells in sar- 

 comatous tissue. The plasma cells may produce the intercellular 

 structures of sarcomata or the^' mav becr>me adult connecti\"e 

 cells and produce fibrous cimnective tissue. 



,01 '5P 





Fig. 15G. — Round cell Sarcoma. 



The rapid development and the irregular distribution of blood 

 vessels predispose sarcomata to destructive processes. Mucoid 

 degeneration frequentlv occurs and may result in the complete 

 destruction of the tumor. Necrosis is also quite common, and 

 suppurative conditions are not rare. If the normal tissues are 

 eroded, exposing the tumor tissue, septic infection is common 

 and sometimes results fatally. 



This group of tumors may be classified, according to their 



