XI 



PARASITIC DISEASES 



HE foregoing chapters were concerned with 



* bacteriology alone, and with those curative 

 or preventive methods of treatment that have come 

 out of inoculation-experiments on animals. The 

 lives that are saved, or safeguarded, by these 

 methods, even in one year, must be many thou- 

 sands in each country of the civilised world. And, 

 beside human lives, there is the protection of sheep 

 and cattle against anthrax, swine against rouget, 

 horses against tetanus, cattle against rinderpest. 

 In Cape Colony alone, so far back as 1899, about 

 half a million cattle had received preventive treat- 

 ment against rinderpest ; and the sum total of 

 human and animal lives saved or safeguarded, in 

 all parts of the world, must be several millions by 

 this time. 



This and the next two chapters are concerned 

 with methods that have come out of experiments on 

 animals, but not out of bacteriology. 



It is plain that the grosser parasites of the 

 human body, tapeworms and the like, could not 

 be explained or understood without the help of 



289 X 



