548 Preston Kyes, 



split the hemoglobin with a freeing of the iron, and finally return 

 to their original form. 



In the spleen, the hemophages are seen in distinctly fewer 

 numbers than in the liver. For the most part they are confined to 

 the pulp cords in contrast to the Malpighian follicles and have no 

 such evident relation to a vessel-wall or-lumen as in the liver. The 

 hemophage however, is morphologically in all of its details of the 

 same type as that of the liver, and the phases of ingestion and 

 digestion of erythrocytes form the same cycle giving the iron reac- 

 tion at corresponding points. 



The plrysiological economy of this destruction of red blood- 

 corpuscles by the hemophages, is conjecture. The iron which is freed 

 and which is eventually lost to the hemophage, is not to be found 

 in the bile: neither is it to be found elsewhere in the tissues of the 

 liver or spleen. This suggests the likelihood of its escape to the 

 blood-stream, with the possibility of its transport to hemopoietic 

 tissues. 



The close chemical relation of the bile pigments to hemoglobin 

 is highly significant in this relation. When it is remembered that 

 bilirubin is approximately if not identically, the iron-free hematoidin, 

 a cell which hemolyses erythrocytes and frees the iron of the hemo- 

 globin is to be seriously considered as playing a role in bile-pigment 

 formation: The location of such cells in the parenchymatous organ 

 from which such pigments are excreted, adds emphasis to the possi- 

 bility of the participation of these cells in bile-pigment formation. 

 I have not as yet been able to demonstrate however, the presence of 

 definite bile-pigments within the hemophages of birds and make no 

 contention in this regard. 



With the recognition of a constant normal phagocytosis of erythro- 

 cytes by the intimai cells of the venous capillaries of the liver and 

 corresponding cells in the spleen, the question arises as to how far 

 these cells differ from vascular endothelium in general; in other 

 words, the extent of their specialization. In reference to this point 

 the evidence shows that the phagocytosis is normally accomplished 

 by endothelium in certain locations only. Thus in the liver, the 



