S62 MICRO-ORGANISMS AND DISEASE [chap. 



gate in the first place are certain cells which do not take up 

 the microbes, which do not act as phagocytes, the latter 

 coming only late into the field. Those non-phagocytic 

 first-comers are the eosinophyle granular cells, which" have 

 the power to destroy the anthrax bacilli with which they 

 come in contact, probably by secreting some matterobnoxious 

 to the bacilli, and that only after this work of injuring 

 the bacilli had been accomplished, the later comers, 

 i.e. the ordinary pale leucocytes, commence to take the 

 bacilli up, to act as phagocytes. These observations of 

 Kanthack and Hardy are very clear and easily verified, 

 and appear to me of the utmost importance, inasmuch as 

 they prove a first process of a change of the bacilli, followed 

 by a second process of scavenging by leucocytes. 



One of the weak points in Metchnikoff's theory of 

 phagocytosis being the primary cause of spontaneous im- 

 munity is the notorious fact that while in some cases of 

 immunity such mechanical phagocytosis — i.e., swallowing of 

 the microbes by leucocytes — cannot be demonstrated, there 

 are other cases not connected with immunity at all, in fact, 

 just the reverse, in which a mechanical phagocytosis is a 

 conspicuous phenomenon : we have in former chapters 

 repeatedly mentioned that if a fairly large dose of active 

 and otherwise virulent diphtheria bacilli (taken from the 

 slanting surface of gelatine), such as would more than 

 suffice to produce tumour and death if injected into the 

 subcutaneous tissue, be injected into the peritoneal cavity 

 of a normal guinea-pig, as a rule no disease or no death 

 follows, the diphtheria bacilli soon disappear from the 

 peritoneal cavity, in fact their degeneration and breaking up 

 can be demonstrated already a few hours after injection. 

 But occasionally in a percentage if the dose be too large, or 

 if instead of gelatine Agar culture is used, disease and death 



