88 RHODA ERDMANN 



before staining and preserving, a half-moon shaped, or elongated 

 nucleus, and their plasma is either granulated, or the granules 

 are invisible dining cell life. The cells shown in figure 2, two 

 granulocytes and one ungranulated large cell, have only been one 

 day in the culture. The first type appears to divide; we can 

 observe smaller forms on the following days, with larger granules 

 than the eosinophil leucocytes possess. The other represented 

 cell type is a large lymphocyte. These forms may break in 

 pieces during observation. After six days incubation we dis- 

 cover in stained preparations the changed form of the myelo- 

 cytes (figs. 39 to 42). The reddish ripened nucleus of these 

 forms has all the characteristics of a myelocytic nucleus. But 

 in eosinazur stains such nuclei are generally supposed to have a 

 more bluish color. This must be explained by the rising acidity 

 of the culture medium in growing tissue cultures (Rous, '13, 

 p. p. 183-86). The cells in figures 39 and 41 must be considered 

 eosinophil myelocytes, those in figures 40 and 42 mononuclear 

 lymphocytes. In earlier stages of their degeneration process 

 these large forms often have very fine acidophil granules in their 

 cytoplasma when observed on the second or third day of incuba- 

 tion; but they are never seen to divide. Their plasma loses its 

 granulations, flattens out, and vacuolizes. The eosinophil myelo- 

 cytes and lymphocytes have only a regressive development 

 in the tissue culture medium. 



THE FATE OF THE FAT CELLS OF THE BONE MARROW IN TISSUE 



CULTURE 



But one observation of the behavior of fat cells in tissue cul- 

 ture is given by Foot, who writes ('12, p. 447,) that the culti- 

 vation of subcutaneous or subepicardial adipose tissue was 

 without success, growth of considerable amount could not be 

 observed. The present writer repeated Foot's experiments. 

 Adipose tissue of the omentum of the chicken showed, after 

 three days incubation, almost a complete disintegration; further, 

 the formation of few cells of the 'cell culture type' and the 

 survival of connective tissue cells could be observed. It may be 

 conceived that some connective tissue cells may have originated 



