168 INTERNAL PAEASITES 



are no full-blooded men and sweet young ladies on the 

 moors? 



LXV 



People who pry into the structure and habits of the 

 humbler forms of life bring to light some strange 

 internal domestic histories. Zoology has been ex- 

 Parasites tended into so many ramifications that it is 

 impossible for any single individual to explore many 

 of them for himself. He must rely on the guidance 

 of the experts who have devoted themselves to the 

 investigation of separate provinces the only way in 

 which any advance can be made in science beyond its 

 present stage. Perhaps the subject which possesses 

 least temptation for the average amateur is the study 

 of those revolting groups of animals which take up 

 their abode within the bodies of man and other 

 animals. Nevertheless, some general acquaintance 

 must be had of these creatures if any idea is to be 

 obtained of the versatility, complexity, and economy 

 displayed in the scheme of nature. No better general 

 view of these internal pirates could be presented than 

 has been done in a recent volume of the Cambridge 

 Natural History a publication which, when com- 

 plete, will constitute the standard British authority on 

 animal life. Messrs. Gamble and Shipley thoroughly 

 competent and trustworthy guides have dealt herein 

 with the endoparasitic groups, and it is worth over- 

 coming the horror which this class of parasite, above 

 all others, excites in the ordinary reader, in order to 



