94 RHODA ERDMANN 



cubation in bone marrow of a young nearly fat-less chicken. 

 Two types besides the erythroblasts with their more or less 

 pinkish plasma and their wheel-like nuclei are distinguishable — 

 cells with crude irregular cell plasma, as if it has been torn 

 They possess small, condensed, highly chromatic nuclei (fig. 8 

 left side, above), or their cytoplasm has well-rounded contours 

 and a very big nearly chromatinless nucleus. This type and 

 its changes will now be described. 



In figures 11 to 27, different emigrated cell types of a similar 

 bone-marrow particle are represented. The particle itself was 

 twice extracted during an incubation period of 24 hours. The 

 emigrated cells of each extraction stayed 12 days in the plasma 

 until they were preserved and stained and later analyzed, so no 

 new rear guard of eosinophil leucocytes and those mononuclear 

 basophil cells, the fate of which Foot tried to elucidate, need be 

 considered. According to this experiment, which was repeated 

 several times, besides the eosinophil leucocytes the changes of 

 which (fig. 11 to 19) have been fully treated on page 85, six 

 different cell types are recognizable after the second extraction. 



1. Cells which resemble fat cells (figs. 20 and 21). 



2. Cells which, by their nuclear structure but not by their 

 cell plasma, resemble true connective tissue cells (figs. 22 to 24). 



3. Cells which are true connective tissue cells, from the type 

 of endothelial cells (fig. 27). 



4. Cells which are true connective tissue cells not shown in 

 figures 20 to 27 but in figure 9, with star-like, fine protoplasmatic 

 processes and elongated, often cone-like shapes, and a more 

 mesenchymelike character. 



5. Cells which are microlymphocytes (fig. 25 and also fig. 27). 



6. Cells which are lymphocytes (fig. 26). 



Cell types 3, and 6 are not often found in preparations made 

 according to the prescribed method. The lymphocyte with its 

 fine red granules (fig. 26) shows all signs of degeneration. It ap- 

 pears highly probable that in the plasma clot the normal ripening 

 out of the large mononuclear lymphocyte began but could not be 

 fully accomplished owing to the conditions of the culture medium. 

 The endothelial cell and the elongated connective tissue cells 



