CHICKEN BONE MARROW IN PLASMA MEDIUM 99 



In the above mentioned preparations the bulk of all cells, 

 with their fat storing and phagocytic capacities, their vacuolized 

 cytoplasm have now left the implanted bone marrow particle. 

 They advance with their fine, pointed, plasmatic pseudopodia to 

 the outskirts of the plasma clot. Their faintly chromatic nu- 

 cleus has only two nucleoli. This character is evident in the 

 youngest cells of that kind w^hich are close to the network of the 

 bone marro^v (figs. 36 and 37) and is also found in 'Wanderzel- 

 len' after Dantschakoff (cf. Dantschakoff, '09, page 133), plate 7, 

 figures 2 to 5. These 'Wanderzellen' w^hich originate from a 

 mesenchyme or endothelial cell can, according to Dantschakoff, 

 either be histiotypic or lymphocytic. They form in the em- 

 bryonal development specific elements of the connective tissue 

 or the hematopoetic apparatus, according to the conception of the 

 monophyletic school. In older cultures nearly all basophil cells 

 have nuclei of true connective tissue cell character, e.i., the chro- 

 matic granules of the nucleus are connected with fine threads. 

 They are identical with those nuclei figured in figures 22 to 24. 

 Not so frequent are types of nuclei figured in figures 20 and 21. 



The 'Wanderzellen' in the tissue culture lose, in the later days 

 of their existence, especially in unrenew^ed tissue cultures, their 

 fine cytoplasmatic processes but are — by the structure of their 

 nuclei and their cytoplasm — connective tissue cells of a more 

 mesenchymelike character. They are transformed to cells of 

 the cell culture type. 



That these cells are descendents of the implanted cells, which 

 were lying close to the bone marrow, is further proved by the fol- 

 lowing experiment. After all loose cells in the meshes of the 

 bone marrow are w^ashed out by repeated changing of the plasma 

 medium, cells of the type in figures 20 to 24, can be formed. 

 After three changes of the culture medium, with a period of 

 two days between, the cells close to the netw^ork formed vacuo- 

 lized cells w^hich could be interpreted in no other way except as 

 'Wanderzellen.' Their nuclei had become nearly chromatinless, 

 and their plasma acidophil; they sometimes assumed the char- 

 acter of fat cells, but were generally of the 'Wanderzellen' type. 



