DIGESTIVE ACTIVITY OF MESENCHYME 441 



Chick (vythrocytes as well as granulocytes may also be found 

 within 'heir cytoplasm. During grafting the production of a 

 slight traumatic hemorrhage can rarely be avoided and erythro- 

 cytes of the host are frequently brought into contact with tumor 

 cells. Small vessels of the host are frequently invaded by 

 tumor cells in later stages of growth; in both cases the tumor 

 cells are seen to contain chick erythrocytes within their cyto- 

 plasm and gradually reduce them to small particles of acido- 

 philic material. 



Numerous granulocj^tes are also found in the tumor cells. 

 It is, however, difficult to decide whether the tumor cell has in- 

 gested these cells or whether the leucocytes entered into a 

 weakened tumor cell, since the structure of both often remains 

 unchanged. Other pictures seem, however, to indicate that 

 tumor cells are capable of digesting chick leucocytes, and both in 

 the resting stage and in mitosis they may contain leucocytes in 

 various stages of disintegration. It seems, therefore, logical to 

 conclude that the tumor cell has a great ingestive and digestive 

 power over its own dead material and over chick erythrocytes 

 and leucocytes. 



The presence of numerous tumor cells acquiring a gigantic size 

 is very characteristic of the Ehrlich sarcoma grown on the 

 chick allantois. A study of the life-history of these giant tumor 

 cells, by means of microscopical preparations, clearly shows that 

 their metabolism becomes gradually modified. 



I have already mentioned that the reconstruction of the chro- 

 mosome complex in tumor cells may be modified by the presence 

 of large quantities of ingested material which offers a physical 

 obstacle to the regular rearrangement of the mitotic figure. In 

 later stages the chromosomes themselves appear strikingly 

 modified in a great number of giant tumor cells. The chromo- 

 somes seldom if ever enlarge, but they are frequently seen to 

 undergo the process of fragmentation and gradual reduction. 

 They appear then in the form of very small rods and even dots. 

 The whole amount of chromatin in the form of the entire chro- 

 mosome complex appears finally reduced. It is remarkable, 

 however, that tumor cells even with greatly modified chromo- 

 somal complexes are still capable of division. 



