TUMOURS AND CANCERS. 



239 



whilst they are yet alive, on a suitable stage, these cells 

 have been found to exhibit amoeboid movements and 

 change of shape.- When such cells die they assume a 

 rounded form, in the same way that a dead leucocyte 

 becomes transformed from an irregular shapeless mass 

 of active protoplasm to a definite rounded cell. 



To put the matter in a clear form, a sarcoma is pro- 

 bably the scene of action of a violent and prolonged 



)^v X^-N /**^\ ^-^\ ff^.T ^;:A /5^/^i 



iMi 



FIG. 121. The microscopic appearance of a round-celled 

 Sarcoma. 



conflict between irritant micro-organisms and leucocytes. 

 I say probably, because, as has been already remarked, 

 bacteriologists have not yet succeeded in isolating a special 

 bacterium for sarcomata in general ; that such agents 

 will soon be discovered is in the highest degree probable, 

 because in recent years each increase in the list of infec- 

 tive granulomata is made at the expense of sarcomata. 

 The structure, mode of growth, infective properties, and 



