270 



«^ro\v MiKi iiuilliply. I'lirllu'rniort' normal tissue cells are 

 not al)l(' lt< l)uikl up Iheir pi'oloplasiii from the serum con- 

 sliluenls or ik-ad tissue cells. 'J'he sarcoma cells are. how- 

 ever, on llu- contrary al)Ie to nuillipiy whcji (lie cells are 

 scattered and isolated yinetaslasis ; tlie>' have the ]>()\ver to 

 synthesise Llieir own })r()toplasm from the serum substances 

 or from dead tissue. On account of this it i.^ ohvious thai 

 the regeneration of normal tissue cells is handicapped. 



The three factors uientioned here as the explanation of 

 the mechanism of the malignity of the sarcoma cells, arc 

 probal)ly no! the only factors playing a role, but in any 

 case they are sufficient to explain the malignity. 



Another problem it would be very interesting to in- 

 vestigate is why the leucocytes in a case of malignant 

 tumor, are not attracted in large quantities, secreting tre- 

 phones necessai'v for the regeneration of the normal tissues. 

 Probably the trephones would not have any influence on 

 the regeneration of the normal tissues, even if there were 

 pk'nty of leucocytes, because of the liquefaction of the 

 fibrin stroma which is caused by the malignant cells. It 

 should be indicated here, that the proteolyzis caused by 

 the malignant cells are probabl}^ also responsible to some 

 extent for the metaplasia of these cells. According to the 

 experiments of l^I h 1 e n h u t h ^^^) and others, we know how 

 the morphology of the tissue cells depends upon the phy- 

 sical conditions of the milieu exterieure. 



It has been stated by several investigators that certain 

 tissues ())• organgs are spontaneous or primary resistant to 

 malignant tissue growth. It has been staled by Murphy "") 

 that spleen tissue, for instance, has an inhibiting effect on the 

 gi'owth of malignant tumors. 



I have therefore tried to add various organs to the cul- 

 tures of R o u s sarcoma instead of the muscular tissue. So 

 far the sarcoma cells have been able to invade, during the 

 process of destruction and disintegration, the various tissues. 

 It was found that spleen had a marked accelerating in- 



