8 QUATERCENTENARY STUDIES IN PATHOLOGY 



injecting sterile broth or normal saline solution into the peritoneal cavity 

 24 hours previous to the injection of red blood cells. One thus inured 

 the phagocytes to insult, and no phagolysis was produced on the 

 subsequent injection of red blood cells. As a consequence, when the 

 erythrocytes were injected, phagocytosis went on readily without the 

 occurrence of extracellular haemolysis. The red cells were hajmolysed 

 only in the interior of the phagocytes. 



From these observations Metchnikofif concluded that the ha^molytic 

 substances in the peritoneal exudate were set free from the leucocytes 

 through the occurrence of phagolysis, and that, as soon as the latter was 

 prevented, haemolysis ceased to occur in the peritoneal fluid and took 

 place in the interior of the leucocyte. 



(2) Metchnikoff further asserted that the presence of alexine or 

 complement or cytase, which occurs in blood drawn from an animal into 

 an ordinary glass vessel, was brought about by injury to mononuclear 

 leucocytes, many of which were broken down during the process of 

 clotting, and thus set free their cytases. This opinion was supported by 

 the experiments of some of his pupils (^) who found that if a vein were 

 ligatured and then excised and suspended, the plasma, which could be 

 pipetted off, contained no cytase; and that, further, if blood were drawn 

 into paraffined glass tubes, no cytase was present, since in neither case had 

 any destruction of macrophages occurred. These views, which were subse- 

 quently supported by the experiments of Tarassewitch (J) and Levaditi, 

 have recently been controverted by Lambottc and Stiennon (S), who 

 have maintained that even when the methods recommended by 

 Metchnikofif were carefully carried out by them, the results obtained by 

 him and his pupils did not ensue. As a result of their experiments, 

 they denied the intra-cellular nature of the cytases. The question of the 

 origin of the cytases is a difficult one, and cannot as yet be regarded as 

 definitely settled. 



The Relationship of the Substances in the Serum producing 

 Haennolysis to the Phenomenon of the Phagocytosis of red 

 blood cells. 



After this short resume of the history of the substances in serum 

 which produce haemolysis, it will be proper to discuss the relationship of 



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