92 . V. E. EMMEL 



tain a comparatively open chromatin network, as is well shown 

 in figure 33 of Maximow's ('09) work. Such modified nuclei are 

 indistinguishable from the irregularly lobulated nuclei of the 

 eosin staining cells in the coelomic cavity. In other words on 

 the basis of the present data the cells in question are evidently 

 correctly interpreted as degenerating nucleated erythrocytes, in 

 which the nuclei are greatly changed in form, the cytoplasm 

 having become deficient in hemoglobin, stains a paler color with 

 eosin and presents the vacuolated condition described by Minot 

 ('12, p. 511) as preliminary to further changes in certain types of 

 erythrocytic disintegration. Here and there fragments of such 

 disintegrated cells can be readily found. Occasionally a cell is 

 observed with a striking peripheral fringe of eosin staining mate- 

 rial. In some cases this material has the appearance of frag- 

 ments of disintegrated cells incidentally resting against or adher- 

 ing to the cell in question. In other instances the union with 

 the cell body is so complete that a question arises whether it 

 may not represent a phase in the degeneration of the hemoglobin 

 containing cytoplasm of the erythroblast (fig. 12). 



How these degenerating erythrocytes come to be situated in 

 the coelomic cavities is more difficult to determine. That cells 

 -with erythrocytic characteristics are normally present constant- 

 ly in the embryonic serous cavities appears positively demon- 

 strated by the character of the cellular inclusions in the macro- 

 phags. In the absence of conclusive data as to their differentia- 

 tion in situ there remains the alternative assumption that under 

 various conditions they may escape from the blood vessels and 

 pass through the coelomic mesothelium into the coelom. Very 

 young erythroblasts may possibly do this by an .active migration 

 although evidence of such a migration was not obtained. It may 

 be noted that ery throblasts may also be found within such extra 

 vascular spaces as the lumen of the Wolffian tubules, occasionally 

 in the lumen of the developing lung buds, and in mesenchymal 

 spaces (p. 603) throughout the embryo. 



