96 V. E. EMMEL 



acter with the bodies under consideration. Perhaps the most 

 constant difference between the bodies in the tissue spaces and 

 the degenerating corpuscles in the vascular channels is the pres- 

 ence of only a small amount or frequently the entire absence of 

 any cytoplasm peripheral to the basophilic rings or spherules in 

 the case of the tissue spaces as compared with the conditions in 

 the degenerating corpuscles of the blood. But this appears 

 readily accounted for on the basis of a more rapid and earlier 

 disappearance of the peripheral cytoplasm of the erythrocytes 

 degenerating in the environment of the inter-cellular fluids. 

 Indeed evidence of such peripheral cytoplasmic changes may 

 be encountered even in the vascular channels as illustrated in 

 figure 36 from a 9 mm. pig embryo in which one of the eryth- 

 rocytes shown contains only a relatively narrow rim of cyto- 

 plasm peripheral to the nuclear ring, whereas it is entirely ab- 

 sent in the remaining two cells. In figure 34a the peripheral 

 cytoplasm of the degenerating erythrocyte is much paler than 

 that of the adjacent normal corpuscle. Instances in the cir- 

 culating corpuscles of nuclear rings without any evident periph- 

 eral cytoplasm is demonstrated in figure 29 from the heart 

 blood of a 7 mm. pig embryo. It appears evident, therefore, 

 that in pig, rabbit and mouse embryos all transitional stages 

 can be found between degenerating nucleated erythrocytes and 

 the eosin, staining bodies in the embryonic tissue spaces. 



A further possible source of origin of many of these bodies 

 which may be noted, especially in older embryos in which non- 

 nucleated erythrocytes are beginning to appear, is in connection 

 with the formation of non-nucleated erythrocytes. In a pre- 

 vious study of the pig embryo (Emmel '14) evidence was ad- 

 vanced indicating the origin of non-nucleated red blood cor- 

 puscles by a process of cytoplasmic constriction resulting in the 

 separation of the original erythroblast into a non-nucleated re- 

 mainder consisting of the erythrocytic nucleus together, not in- 

 frequently, with a small amount of cytoplasm remaining from 

 the parent cell. This nucleated remainder may present an ap- 

 pearance practically identical with that of many of the eosino- 

 phihc bodies under discussion. 



