ARTIFICIALLY PRODUCED IMMUNITY. 765 



rabies, need hardly be recalled, any more than the fact that 

 by using medullas in various stages of desiccation he was able, 

 with Eoux and Chamberland,' to completely immunize dogs 

 from the bites of rabid animals. 



When the method is employed in human beings, a small 

 piece of desiccated cord is rubbed up in sterile bouillon and 

 some of the fluid thus prepared is injected at intervals. 

 Wherein does this method differ, in the light of our views, 

 from injections of an equally active alkaloid? Simply in this: 

 We have seen that poisons differ as regards the energy with 

 which they stimulate the adrenal system; by using the toxin 

 of a given bacillus we are at least reasonably certain that the 

 vigor with which the adrenal system will be stimulated will 

 prove adequate to cause the production of sufficient oxidizing 

 substance, fibrinogen, and trypsin to fully master the morbid 

 process: a result which a weaker agency might fail to insure. 

 There is a degree of precision in the use of the methode in- 

 tensive, therefore, that the use of other agents to offset the 

 disease would not afford. 



Still, we have only, so far, referred to the manner in which 

 the morbid effects of germs and toxins are counteracted; an- 

 other question presents itself, however: i.e., How is the im- 

 munity prolonged, as it is by vaccination against small-pox, 

 for example, and various diseases? This may be illustrated by 

 a brief reference to vaccination. 



Vaccination against Small-pox. In this method, as now 

 practiced, the "lymph" obtained from pocks of young calves is 

 the inoculating agent. The nature of the infecting agent as 

 in the case of rabies has remained undiscovered; but it evi- 

 dently differs as to its mode of action from that of the virus of 

 the latter disease, since, instead of insufficiency, it gives rise to 

 a febrile reaction and other phenomena of marked adrenal over- 

 activity. That this adrenal reaction sometimes exceeds its nor- 

 mal limits is illustrated by the cases of tetanus that have been 

 recently observed after vaccination. Under these circumstances 

 adrenal insufficiency occurs precisely as in true tetanus, but is 

 preceded by a primary stage of overactivity which the adrenals 

 of the various subjects are not able to stand. 



We have clear evidence here that inordinate functional 



