178 THE STORY OF GERM LIFE. 



great things in the future. If it was thus possi- 

 ble, by direct laboratory methods, to find a 

 means of inoculating against a serious disease 

 like anthrax, why could not the same principle be 

 applied to human diseases ? The enthusiasts be- 

 gan at once to look forward to a time when all 

 diseases should be thus conquered. 



But the principle has not borne the fruit at 

 first expected. There is little doubt that it might 

 be applied to quite a number of human diseases 

 if a serious attempt should be made. But several 

 objections arise against its wide application. In the 

 first place, the inoculation thus necessary is really 

 a serious matter. Even vaccination, as is well 

 known, sometimes, through faulty methods, re- 

 sults fatally, and it is a very serious thing to 

 experiment upon human beings with anything so 

 powerful for ill as pathogenic bacteria. The seri- 

 ousness of the disease smallpox, its extraordinary 

 contagiousness, and the comparatively mild results 

 of vaccination, have made us willing to undergo 

 vaccination at times of epidemics to avoid the 

 somewhat great probability of taking the disease. 

 But mankind is unwilling to undergo such an op- 

 eration, even though mild, for the purpose of 

 avoiding other less severe diseases, or diseases 

 which are less likely to be taken. We are un- 

 willing to be inoculated against mild diseases, 

 or against the more severe ones which are 

 uncommon. For instance, a method has been 

 devised for rendering animals immune against 

 lockjaw, which would probably apply equally 

 well to man. But mankind in general will never 

 adopt it, since the danger from lockjaw is so 

 small. Inoculation must then be reserved for 

 diseases which are so severe and so common, or 



