264 Bacterio- vaccines 



of the cholera spirillum as a prophylactic against cholera, and later 

 with equal success, heated and killed cultures of the plague bacillus 

 as a prophylactic against plague. Wright somewhat modified the 

 method, by using two or even three doses of modified cultures of 

 the typhoid bacillus at intervals of ten or even twenty days, to secure 

 complete prophylaxis against typhoid fever. 



From prophylactic measures it was but a step to therapeutic 

 measures, and the endeavor to facilitate the cure of disease by the 

 administration of cultures of vaccine. The patient suffering from 

 an infectious disease was already impressed by the toxic, enzymic 

 or other disease-producing substances in his body, and the ad- 

 ministration of cultures of micro-organisms seemed like adding 

 so much fuel to an already widespread conflagration. Indeed, 

 experience and experiment seemed to prove this to be the case, for 

 when by any mischance a patient in the early stages of plague 

 received an injection of the Haffkine plague prophylactic, he straight- 

 way became much injured by the added culture and might even 

 die quickly. 



But there are certain infections in which conditions are different 

 both with regard to the bacteria and the disease. Thus, a certain 

 micro-organism with limited power of invasion and with difficultly 

 soluble toxic products (endo- toxins), whose injurious effects are 

 local and limited in extent, particularly when their effects are pro- 

 longed and the disturbances chronic, are essentially different from 

 actively invasive agents that quickly over-run the body, or those 

 with considerable soluble products by which it is generally disturbed. 



In the former group it is not unreasonable to hope that through a 

 method of treatment by which the general body defences are stimu- 

 lated, the local infections may be overcome. Such cases of dis- 

 ease were, therefore, selected, especially by Wright, for investi- 

 gation and treatment. Success of varying degree has followed, 

 and though it is difficult to calculate accurately the benefits obtained 

 in cases that are not susceptible of numerical expression, the almost 

 uniform opinion of clinical and laboratory men is to the effect that 

 certain cases of sluggish infection, with little tendency to recover are 

 benefited and sometimes rapidly cured by treatment with bacterio- 

 vaccines. 



From these preliminary considerations it should be clear to the 

 reader that the theoretical conditions necessary to success are the 

 following: 



1. That the disease should be of subacute or chronic duration. 



2. That it should be fairly well localized. 



3. That it should be caused by a micro-organism incapable of ready invasion 

 or much soluble toxin formation. 



4. That the micro-organism be known and capable of cultivation so that the 

 appropriate-specific vaccine can be made. 



From these conditions certain lesions resulting from infection by 

 pus cocci, colon bacilli, acne bacilli, typhoid bacilli (post-typhoidal 



