INFECTION AND IMMUNITY. 473 



Pawlowsky, 1 who obtained similar results from the 

 introduction into the animal of cultures of bacillus 

 prodigiosus, of staphylococcus pyogenes aureus, and of 

 micrococcus 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 that is afforded in this way apparently 

 con train dicates a specific relation between the morbific 

 elements 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 Mattei and of Paw- 

 lowsky can be explained in another way: in the blood of 

 animals there is present what may be termed a normal 

 protective (Buchner's alexines) having no specific rela- 

 tions to any particular variety of infection, but serving 

 to protect the animal more or .less completely against all 

 bacterial invasion. By the methods employed in the 

 preceding experiments it seems likely, in the light of 

 more recent work, that this normal antidote was simply 

 temporarily accentuated through the tissue-stimulation 

 resultant upon the treatment that the animals had re- 

 ceived, for it has never been shown to be possible to 

 bring about as high or as permanent a degree of im- 

 munity in an animal from a particular disease as that 

 which can be obtained by the use of the specific micro- 

 organism causing the disease, or the products of its 

 growth, especially the latter. 



1 Pawlowsky : Virchow's Arch., vol. cviii. p. 494. 



