INDIVIDUAL DIFFERENCES 



skill and care to bring before the world the true and 

 faithful representations of the nervous, digestive, and 

 other organs of the common blow-fly ? Why can this 

 humble individual require to be so well furnished with 

 these structures, at one time thought to belong only to 

 creatures of a much higher order ? Have we not been 

 shown that this little fly has a brain and nervous system 

 most complete and perfect in its way ? Has, then, the 

 smallest fly this same kind of organization, and which we 

 have not yet made microscopes sufficiently perfect to dis- 

 cover? Few persons would be able to distinguish one 

 flea from another, but the proprietor of the exhibition of 

 the " industrious fleas '' knew each individual perfectly, 

 and called them by different names, alleging also that 

 the fleas differed much in disposition and temper, a fact 

 that those who have had the experience of meeting large 

 numbers of them will not doubt. 



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