396 BACTERIOLOGY. 



ference to what is already known of the physio- 

 logical protective forces of the body and the 

 manner in which they are stimulated or called 

 into activity. The specific methods of calling 

 the bodily forces into activity are usually to be 

 preferred, since stimuli of this character bear 

 a recognized relation to the defensive organs 

 of the body, but by this I do not mean to claim 

 that they are the sole or always the best means 

 of producing the desired effect. Any such 

 notion as the doctrine of specificity must be 

 set aside if we do not wish to bar the road to a 

 scientific interpretation of immunity. A pro- 

 tective inoculation may appear specific not 

 only when it is brought about by isopathic or 

 specific bacteria and their products, but also 

 when it is attained by means of stimuli of a 

 wholly different kind. On the other hand the 

 use of appropriate specific stimuli may call 

 into activity only defensive contrivances of a 

 slight and generalized character. 



The question is not whether something is 

 demonstrated or demonstrable in every case, or 

 whether it is the best or most practical thing, 

 but it is rather whether the thing exists at all. 

 We are able to trace back the various forms of 

 specific habituation to poison and protective in- 

 oculation, like those of natural curative and pro- 

 tective power, to the same general natural law 



