94 V. E. EMMEL 



Since these structures are so closely similar to the small eosin- 

 ophilic elements occurring in the coelomic cavities it became 

 necessary to reexamine the evidence for an intra-cellular origin 

 of such bodies. For the writer the subject had also an addi- 

 tional interest in consequence of a previous study of the cyto- 

 logical differentiation of erythrocytes in which there was occa- 

 sion to consider the possible origin of erythrocytic or hemo- 

 globin containing elements in the cytoplasm of the mesenchymal 

 cell (Emmel '14). 



As already indicated, the preceding results of the present in- 

 vestigation with reference to the eosinophilic bodies in the 

 coelom were negative as to their origin as intra-cellular secre- 

 tions. Furthermore after careful study I have been unable on the 

 following grounds to convince myself that the bodies described 

 by Maximow in the mesenchyma necessarily represent intra- 

 cellular secretions of mesenchymal cells. In the first place 

 these eosin staining bodies are found equally as abundant and 

 indeed frequently even more so within the ectodermal tissue of 

 the brain wall (fig. 33e) cranial and spinal gangUa (fig. 28) and the 

 entoderm of the growing lung buds and digestive tube, in situ- 

 ations where they would be least expected if they are derivatives 

 of mesenchymal cells. They also occur in inter- as well as intra- 

 cellular situations. 



Figure 31 is from the mesenchyma in the ventral thoracic 

 wall of a 9 mm. pig embryo and figure 32 from the mesenchyma 

 of the septum transversum of a 7 mm. pig embryo. It will be 

 observed that in both cases practically all the eosinophilic 

 bodies in question are clearly situated in inter-cellular mesen- 

 chymal spaces. Similar relations can also be readily demon- 

 strated in the brain wall and the cerebrospinal nerve ganglia 

 (fig. 28). On the other hand similar bodies can also be found 

 which appear unquestionably situated within the cytoplasm 

 of cells in the mesenchyma. Since these bodies are both inter- 

 and intra-cellular in position it seems clear from this aspect of 

 the subject that they may be as adequately interpreted as either 

 extra-cellular elements, some of which may have become phag- 



