UK) KHODA EUDMANN 



No large mononuclear lymphocytes could be seen. It is, 

 therefore, also evident that a new formation of this cell type, 

 the niononuchar hir^e lymphocyte of the bone marrow, does not 

 occur in i\\v tissue culture. The smaller and larger basophil 

 cells with a vesicular nucleus near the bone marrow network, 

 and the cells which later leave the network are 'Wanderzellen,' 

 a type closely related to the mesenchymal cell. They can be 

 kept alive for longer periods in renewed culture-medium. 



The empty network of the bone marrow, consisting of slender 

 connective tissue cells, has lost its power of sending new cells 

 into the surounding plasma clot. The network cells remain liv- 

 ing for long periods in renewed medium changing only their cyto- 

 plasma in the same manner as other connective tissue cells do in 

 plasma culture. It becomes perforated with sieve-hke vacuoles 

 which may store fat. 



SUMMARY 



The growth of chicken bone marrow in chicken plasma may be 

 divided into two distinct periods. The first period has a more 

 regressive character. As process of this first period may be 

 enumerated: — the degeneration of the erythrocytes and the 

 nearly full-grown erythoblasts, the ripening of the granulocytes 

 implanted with the bone marrow into the tissue culture; and the 

 decay of the latter. 



The eosinophil mononuclear or polymorphonuclear leucocytes 

 after rapid multiplication lose their granules, are flattened out, 

 and form cell chains of acidophil character which undergo slow 

 destruction. 



The myelocytes moving at first amoeboid-like in the plasma 

 clot, and behaving like phagocytes, seldom divide, but ripen out 

 until they assume a large size. Then their plasma vacuolizes 

 and disappears, leaving only the nuclei. 



The microlymphocytes show no signs of multiplying. They 

 leave the meshes of the bone marrow particle; later lose their 

 cytoplasm; and finally leave their condensed nuclei in the 

 culture. 



