THE HISTOGENESIS OF DENSE LYMPHATIC TISSUE 187 



blasts or slightly smaller (fig. 9). The mononuclear forms of 

 rodded eosinophiles present the next step in nuclear differentia- 

 tion, being similar to the 'hemoblast' type, but smaller and 

 with more condensed chromatin material. By division of this 

 nuclear material into two parts the binucleated rodded eosino- 

 phile leucocyte is produced. All transitional stages between 

 mononuclear and binuclear forms can easily be found. First 

 the round nucleus assumes an oval form, then an indentation 

 appears in one side, and soon the two parts thus divided begin 

 to pull apart, forming two lobes with a connecting strand. This 

 connection seems gradually to disappear, so that there are 

 apparently two distinct nuclear masses in the cell (figs. 10, 16). 



In the production of granulocytes, then, the cytoplasm of 

 involved lymphoid hemoblasts, the cells of origin, partially (as 

 Maximow states) or entirely lose their basophilic character. 

 After the basophilic character of the cytoplasm is lost, rounded 

 eosinophile granules are formed endogenously in it, the nuclei 

 at the same time decreasing in size. These granules increase 

 rapidly in size and number, at the same time changing into a 

 rod-hke shape (in the rabbit). Soon .the eosinophile particles 

 fill all available space in the cytoplasm of the cells. Coincident 

 with this is noted a continued decrease in the size of the nuclei 

 with correspondingly increased density of the chromatin material. 

 The change from the mononuclear to the binuclear form, as 

 described above, apparently occurs after the cytoplasmic changes 

 have been completed. This binucleated form is, as far as can 

 be determined, the adult forpi of the connective-tissue eosino- 

 phile as occurring here. 



Concerning the possibilities of homoplastic formation of eosino- 

 philes, it certainly does not occur in the blood eosinophiles found 

 in the connective tissue. No mitotic figures were seen in this 

 type, as might be expected, for they are only present here in the 

 adult condition. Mitotic figures in adult connective-tissue 

 eosinophiles are never seen. They have been reported (by Dan- 

 chakoff and Weill) in developing granulocytes or granuloblasts. 

 The writer found no eosinophiles showing evidences of mitosis 

 after granules had begun to be formed. This, then, as a source 



