253 



The intcresling fact was learned, Ihal the sarcoma cells seem 

 lo be able to transform Ihc protoplasm of the muscular tis- 

 sue into protoplasm of tiicir own. Only a trace of embryonic 

 tissue juice was added to the culture medium, in order to 

 obtain a quick coagulation and a firm clot. A whole scries 

 of cultures of sarconui cells have been cultivated now for 

 more than two months without the slightest embryonic 

 tissue juice. We are now able better to underslami the 



Fig. 61. 

 Represents a section ttirougti a culture of ttie Rous sarcome after a couple of 

 month's cultivation. An infiltration of the muscle fragment can be seen. 



malignant, parasitic character of the sarcoma cells, when 

 they in vivo are able to attack the normal healthy cell and 

 destroy it. 



It can now be concluded, that the muscular tissue, stored 

 in the ice-box for a long period of time is just as good 

 a food for the sarcoma cells as the freshly extirpated. So 

 far it has been possible to cultivate the Rous chicken sar- 

 coma in vitro for about 2 years with the addition of 



