HEMOLYSIS AND PHAGOCYTOSIS OF RED BLOOD CORPUSCLES 5 



macrophages. In the peritoneal cavity, some time after such an injection, 

 an accumulation of leucocytes takes place. Amongst these are to be 

 found all kinds of white cells, but the mononuclear macrophages 

 predominate, the polymorphonuclear microphages playing quite a minor 

 role. The macrophages take up the alien cells, and proceed to digest 

 them by means of certain ferments which, according to Metchnikoff, 

 they contain. These ferments he termed cytases. 



Relationship of Cytases to Haemolysis. 



Now, the spleen and lymph glands are organs composed mainly of 

 macrophages, and if one make extracts of such organs with normal 

 saline solution, one obtains, according to Metchnikoff, an extract of 

 macrophages. Such extracts or emulsions cause haemolysis of red 

 blood cells, i.e., they cause the haemoglobin to diffuse out, This 

 haemolytic function of the macrophage extracts, he held, depended on a 

 special substance which they possessed. This substance was destroyed 

 by heat at 56" C. for f to i hour, i.e., it was thermolabile. Now, since 

 this property of haemolysis was found to be possessed by the blood 

 serum of animals into which red blood cells had been injected, it 

 appeared to Metchnikoff that the substance in the macrophage extract 

 was identical with that in the serum, and he was of the opinion 

 that in both cases it was an unformed ferment or cytase, which, since it 

 was derived from the macrophages, he termed macrocytase. The cytase 

 which the polymorphonuclear leucocytes contained, he called microcytase. 



Views of other Researchers on this Subject. 



These views on the cytases and their origin did not long remain 

 unchallenged. It was denied by Korschun and Morgenroth (i) that the 

 haemolytic action of macrophage extracts was due to a thermolabile 

 cytase, and in support of this view, they asserted that heating at 56° C 

 did not cause the disappearance of the haemolytic property of macrophage 

 extracts, and that they even bore the temperature of the boiling point 

 before giving up this power. They showed, too, that the haemolytic 

 substance in macrophage extracts was soluble in alcohol, and quite 

 different from the true enzymes or cytases, and therefore different from 

 the thermolabile cytase in the blood serum. 



(305) V 



