INFECTION AND IMMUNITY. 557 



a product that is detrimental to the patiiogenic activity 

 of the anthrax bacilli. In a later paper' Emmerich, in 

 association with Low, offer still another explanation for 

 the phenomenon. They believe that the protection 

 afforded an animal from a specific infective organism 

 by the injection into it of another organism or the 

 products of its growth is due to the direct bacteriolytic 

 action of the enzymes peculiar to the latter upon the 

 former species. In their opinion, the enzymes of the 

 latter organism enter into a more or less stable combina- 

 tion with the living protoplasm, and in this state are 

 actively destructive (digestive) for the invading patho- 

 genic species. 



Pawlowsky,^ who obtained similar results from the 

 introduction into animals of cultures of hacillus pro- 

 digiosus, of staphylococcus pyogenes aureus, and of mi- 

 crococcus lanceolatus, believes them to be due to the 

 induction of increased energy on the part of the wan- 

 dering cells, preparing them thus for the difficult task 

 of destroying the more virulent organisms with which 

 the animal is subsequently to be inoculated. 



Protection afforded in this way apparently contra- 

 indicates a specific relation between the morbific ele- 

 ments of particular infections and the protective sub- 

 stances that are present in the body of the animal that 

 has been rendered insusceptible to them. It is proba- 

 ble, however, that this is only apparent, and that the 

 observations of Emmerich and Mattel and of Paw- 

 lowsky can be interpreted in another way: in the blood 

 of animals there is present what may be termed a nor- 



2 Emmmerich iind Low : Zeitschrift fiir Hygiene und Infektlons- 

 krankheiten, 1899, Bd. xxxi. S. 1-65. 

 ' Pawlowsky: Virchow's ArcMv, vol. cviii. p. 494. 



