546 Preston Kyes, 



protruding hemophages of greater bulk, the nucleus is more vesicular 

 and is irregularly pyramidal in form. Two nuclei may be found 

 within a single cell, but rarely. 



The most striking characteristic of the hemöphage however, is 

 the morphology of its cell-body. This is determined by the fact that 

 within vacuoles of the cytoplasm, are contained red blood-corpuscles taken 

 from the circulating blood stream. It is not meant that here and there 

 may occasionally be found a hemophage which has taken up an erythro- 

 cyte, but rather that the occurence is general and that approximately one 

 third of the total intimai cells are hemophages and that each hemophage 

 displays evidence of containing or having recently contained, one or 

 more erythrocytes. The fact that the red blood-corpuscles of birds 

 are nucleated, have a denn ted ovoid outline, and are of relatively 

 large size, allows clear observation as to their actual inclusion and 

 ultimate intracellular fate. The cell-body of the hemophage has no 

 fixed morphology but changes from time to time according to the 

 phase of its phagocytic activity. Within a single field of the micro- 

 scope may be seen all intermediate stages between the hemophage 

 whose cell-body is greatly distended by an intact erythrocyte recently 

 ingested and the hemophage which has so far completed the destruction 

 of the erythrocyte as to again appear as a flat endothelial cell except 

 for the presence of the traces of the end-products of the digestion 

 (Figs. 2 — 4). In the first instance the cell-body of the hemophage 

 bulges markedly into the capillary lumen and its nucleus is crowded 

 to one side. The included erythrocyte in this earliest stage appears 

 in all ways the same as those of the blood-stream and displays a normal 

 staining reaction; namely, by the technique outlined, its nucleus stains 

 a deep redbrown, while its cytoplasm stains an even yellow-bronze 

 tone. In the very earliest stages the cytoplasm of the hemophage 

 gives no iron reaction, but in the next-following stage in which also the 

 erythrocyte appears normal, the cytoplasm of the hemophage gives a 

 diffuse Prussian-blue reaction (Figs. 3 and 4, a). In hemophages which 

 represent the subsequent stages, the included erythrocytes are seen in 

 various stages of disintegration and digestion while the cytoplasm of 

 the including cell gives a constant iron reaction (Figs. 2 — 4, a). The 



