262 ANATOMY OF THE DOMESTIC FOWL 



cells. They vary much in size and form. They bear a constant 

 relationship to the venous capillaries, and often appear to occupy 

 the lumen of the vessels. Under higher magnification it is noted, 

 however, that each cell is an integral part of the endothelial intima 

 lining of the capillaries. They are therefore fixed tissue cells, en- 

 gaged by one of its surfaces upon the reticulum of the vessel wall, 

 with a free surface bulging a greater or less degree into the lumen 

 of the vessel. The attached surface of the cell follows exactly the 

 line of the vessel wall. These cells are similar to those described 

 for mammals by Kupffer and are called Kupffer cells or stellate 

 cells. In the fowl Keys proposes the name hemophages. The 

 nucleus of the hemophage stains a deep garnet with the carmine used 

 hi the above-given technic, and contains two or three very dis- 

 tinct and intensely stained nucleoli. In the hemophages, which are 

 more nearly flat, the nucleus appears like those of the typical endo- 

 thelial cells; whereas in the protruding hemophages of greater bulk, 

 the nucleus is more vesicular and is irregularly pyramidal in form. 

 Rarely two nuclei are found in one cell. Within this cell may be 

 seen vacuoles of the cytoplasm which contain red blood corpuscles. 

 These blood corpuscles have been phagocyted from the circulating 

 blood stream. Approximately one-third of the intimal cells are 

 hemophages. Each hemophage displays evidence that it contains, 

 or has recently contained, one or more red blood cells. The cell body 

 of the hemophage has no fixed morphology, but changes from time 

 to time according to its phase of phagocytic activity. In a stage 

 which the hemophage has recently ingested a red blood cell, the 

 cell body bulges out into the lumen of the vessel and the nucleus is 

 crowded to one side. At this time the red blood cell appears as 

 those in the blood stream and possesses the characteristic staining 

 reactions. The nucleus of the red blood cell stains deep reddish 

 brown and the cytoplasm an even yellow bronze. In the next stage 

 the cytoplasm of the hemophage gives a diffuse Prussian-blue reac- 

 tion. Then in hemophages which represent later stages there are 

 various stages of disintegration and digestion of the red blood cell. 

 The first changes of the phagocyted red blood cell is hemolysis, the 

 hemoglobin escaping into vacuoles of the cytoplasm of the phago- 

 cytic cell, leaving the nucleus-containing stroma distinctly outlined. 

 The stroma may retain the original ovoid form or may become spher- 

 ical; the nucleus in such instances remains ovoid. Gradually, both 

 the stroma and nucleus lose their staining reaction until finally the 



