552 Chapter XVII 



[576] and digest them within their substance. Just as it is easy, in 

 situations populated by pre-existing leucocytes, to suppress the 

 extracellular destruction of the micro-organisms by preserving the 

 phagocytes against injury or phagolysis, so this same extracellular 

 destruction is easily set up in situations where leucocytes are absent. 

 When, after exudations rich in leucocytes have been injected into 

 the subcutaneous tissue, we introduce micro-organisms which are not 

 very resistant, such as the cholera vibrio, it is observed that these 

 vibrios are destroyed outside the cells, having first been transformed 

 into granules. 



There can be no doubt as to the conclusion to be drawn from these 

 various experiments. The microcytase is the substance which trans- 

 forms the vibrios into granules. It is within the microphages, when 

 they remain intact, that the vibrios undergo transformation. When, 

 on the other hand, the microphages are injured and allow the micro- 

 cytase to escape, the transformation of the vibrios into granules 

 and their partial destruction take place in the plasmas outside 

 the phagocytes. 



This conclusion is supported by comparative researches on the 

 bactericidal power of the serum and of the blood plasma outside the 

 animal. It is true that it is impossible to prepare a fluid which 

 shall in all respects be comparable to the plasma of the circulating 

 blood. There is, however, always a means of obtaining outside the 

 animal a fluid which approaches much more closely to blood plasma 

 than does serum. Gengou succeeded in preparing in tubes coated 

 internally with paraffin a fluid which coagulates very tardily, and 

 which contains very little fibrin-ferment. This fluid is found to be 

 much less bactericidal than is the blood serum of the same animal. 

 It is, indeed, often found to be entirely without bactericidal power, 

 whilst the corresponding serum is capable of destroying a large 

 number of micro-organisms. 



In the phenomena of the absorption of cells also a great number 

 of facts are met with which demonstrate that the macrocytase 

 escapes from the macrophages at the moment of their phagolysis 

 only. For example, the extracellular solution of the red corpuscles 

 takes place easily in the peritoneal fluid of animals prepared by 

 a previous injection of the same corpuscles. When the leucocytes 

 of the peritoneal cavity are abandoned to their fate, a marked 

 phagolysis is produced and consequently a solution of the red 

 corpuscles in the fluid itself. When, on the other hand, phagolysis 



