2 LECTURES. 



better enforced than by an appeal to the record 

 of our recent experiences in regard to the life- 

 history and economy of the entozoa. Here, be 

 pleased to observe, we have a group of creatures 

 (hitherto mysterious to us in respect of their varied 

 modes of origination and entry into the human 

 body) showing peculiarities in their organization 

 and displaying migratory habits, associated with 

 metamorphotic changes altogether unique ; and so 

 strange are these phenomena, when viewed in re- 

 ference to the ends accomplished, that I believe 

 I am not going too far in stating that their fair 

 consideration is certain to overthrow the ordinarily 

 received opinions of teleologists respecting the why, 

 how, and wherefore of their mere existence. 



This, however, is not the place to enter upon 

 speculations which can tend to little practical 

 good ; nevertheless I will venture to remark in 

 passing that I still think it possible to entertain 

 conceptions of original causation in harmony 

 with the doctrine of final causes, provided only 

 you express that doctrine in terms sufficiently 

 wide. 



Be that as it may, gentlemen, it is perhaps 

 sufficient for you to concern yourselves with the 

 fact that the entozoa, the helminths, the intestinal 

 worms, or call them what you will, are capable, 

 both individually and collectively, of producing the 

 gravest of maladies. Thus a single parasite, no 



