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IMMUNOLOGY 



round, or sometimes a kidney-shaped nucleus but never possesses 

 a rosette, and, when material is phagoeytized, it appears in vacuoles 

 near the nucleus. In Plate II, Fig. 5, a clasmatoeyte is shown con- 

 taining a neutrophile leucocyte within a vacuole. The neutrophile 

 is apparently dead since its nucleus is stained with neutral red. 

 The concentration of neutral red used in this preparation will not 

 stain a living nucleus. 



Gay (1931) has illustrated the various types of cells and in- 

 dicated their possible origin and function as described by various 

 authorities. His portrayal of these facts is reproduced in Fig. 5. 



Fig. 5. — The supposed intergenetic relationships and convertibility of cells 

 of the "macrophage (reticulo-endothelial) system" of mammals. The authorities 

 mainly responsible for the supposed changes are given on the arrowed lines. 

 Heavy lines indicate more generally accepted type cell changes; dotted lines 

 show less authenticated or more recent conceptions. Prom Tissue Resistance 

 and Immunity, by F. P. Gay, v. 27, p. 1195, 1931, Journal American Medical 

 Association. By permission of F. P. Gay and Journal American Medical Asso- 

 ciation. 



It will be observed from an inspection of Gay's illustration that 

 all are agreed that the large mononuclear phagocytes are produced 

 for the most part in the spleen, liver, and lymph glands. While 

 a few are produced by the bone marrow, it seems that its function 

 is largely that of producing red cells, platelets, and granulocytes. 



