TAPEWORMS. 6 



larger than a pea, and whose presence in the human 

 body shall never have hitherto occasioned the 

 slightest inconvenience to the " bearer " of it, may, 

 without a moment's warning, give rise to instan- 

 taneous death; whilst, on the other hand, collec- 

 tions of parasites, each individually so small that 

 thousands of them might be placed in a nutshell, 

 are capable of producing equally fatal results, some- 

 times affecting a whole community. 



Surely then, at a time when chairs are founded 

 to promote the knowledge of dermatology, when 

 societies are created to discuss questions of epi- 

 demiology, and when associations are formed 

 solely with the benevolent purpose of advancing the 

 interests of public health, I am not going out of 

 the way in insisting more precisely than has hitherto 

 been done on the claims of helminthology. 



With these preliminary remarks, let us attack 

 our subject by treating of those human parasites 

 which, though not the most common, are perhaps 

 the best known I mean the tapeworms. In re- 

 spect of their general structure and development, it 

 is important to remind you that in a separate 

 specimen, such as is ordinarily obtained from the 

 hospital, you have to deal with a multiple sort of 

 creature, whose various " joints " or segments, 

 whether sexually mature or otherwise, represent so 

 many individual- like beings arranged in single 

 file. A fully developed beef tapeworm numbers 

 B 2 



