257 



Cultures of sarcoma cells show often a different picture. 

 Aftei' 24—18 hours incubation, one maj^ find sarcoma cells 

 scattered almost all over the culture medium. This and 

 the fact, that one single sarcoma cell is sufficient to con- 

 taminate a piece of dead muscular tissue and give rise to 

 unlimited quantities of sarcomatous tissue, explains the re- 

 lative independency of the sarcoma cells. 



For the study of the cell division of the sarcoma cells, 

 cultures were prepared of Rous chicken sarcoma and a 

 few human sarcomata, an osteosarcoma and glio-sarcoma. 

 The human tissues were prepared for cultures shortly after 

 removal from the patients by operation. The culture medium 

 for the Rous sarcoma which was found most suitable, was 

 composed of two volumes chicken plasma and a trace of em- 

 bryonic tissue juice. If too much embryonic tissue juice 

 was added, an extensive liquefaction occurred in the plasma 

 clot. The culture medium used for the human tissues, was 

 composed of varying amounts of human plasma and chicken 

 plasma and an addition of extract from the respective 

 sarcomata or human muscular tissue. 



It proved to be less difficult to obtain isolated individuals 

 of sarcoma cells, than was the case with the fibroblasts. 

 The observations were made during the first passages or 

 after the sarcoma cells had been cultivated for about 11 

 days to 8 weeks. Usually it was not necessary to make 

 special arrangements for getting isolated cells for the obser- 

 vations. The cells behaved in that respect differently from 

 the normal fibroblasts; the tendency to form tissues is not 

 excessive. In all the cultures it was eas}^ to find perfectly 

 isolated cells in the periphery of the cultures. The cells are 

 usualh^ very active ameboid and migrated far out into the 

 culture medium. 



The sarcoma cells foi'ui very loose connections with other 

 cells, compared with those of normal tissue cells and be- 

 sides that, they liquefy the plasma very intensively. This 

 was made use of in aspirating the liquefied plasma, includ- 



17 



