IMMUNITY. 367 



cholera serum. We may infer that it is the 

 leucocytes and the substances derived from 

 them which effect the change of the comma 

 bacilli into granules, from the fact also that 

 the ;ame sort of disintegration takes place 

 within the leucocytes. If bouillon be injected 

 into the peritoneum before the injection of the 

 bacteria mixed with serum, the disintegration 

 of the leucocytes does not take place, but pha- 

 gocytosis of the bacteria immediately begins 

 and the germs are in part transformed into 

 spherules inside of the phagocytes. One point 

 appears certain, and is in accord with Hankin's 

 observation, namely, that at least those active 

 proteid bodies of the serum, which apparently 

 arise from the white blood-corpuscles included 

 under the term phagocytes, are able to exert a 

 damaging effect upon micro-parasites, and that 

 therefore the condition of the body-fluids is not 

 in every case a matter of indifference. But 

 such a condition of the fluids really depends 

 upon the influence of the cells. 



The bactericidal substance, therefore, which 

 constitutes the protective substance or alexin 

 of the blood plays an important part in the liv- 

 ing body, but it is only one of the manifesta- 

 tions of phagocytic activity, since it is possible 

 by means of specially devised experiments to 

 suppress this chemical bactericidal action with- 



