CH. XX.] HISTORY OF THE FLEA. 275 



but which is, nevertheless, so deeply rooted, that it 

 requires " line upon line, and precept upon precept," 

 to dislodge it from the minds even of well-educated 

 persons. 



Descending, however, from fiction to plain matter 

 of fact, we propose in this chapter to detail the 

 natural history and series of transformations which 

 the insect first mentioned undergoes previous to 

 appearing in its perfect state, and which, although 

 our readers may probably have no idea of their ex- 

 istence, are not less remarkable than those of the 

 buttei-fly or the beetle. 



It appears that Aristotle was the first author who 

 was acquainted with any of these changes, since he 

 noticed not only that the flea has distinct sexes, but 

 that it produced oKioXrjs S)oti5e~is ; from not, however, 

 tracing the insect through its different states, he 

 fancied this progeny was completely sui generis and 

 imperfect, and that the perfect insect was generated 

 spontaneously in the earth, just as at the present 

 day plant-Hce, turnip-flies, &c., are supposed to be 

 generated spontaneously in the air. Indeed, as Mr. 

 Mac Leay observes, it is always either at the egg 

 or pupa state that Aristotle, and, we may add, many 

 other naturalists, have lost sight of the metamor- 

 phosis, and, in the absence of experiment, have had 

 recourse to fancy. Hence, the name given to this 

 insect by the Romans, Pulex, is stated by Isidorus 

 to have been derived from pulvis,* dust, quasi pul- 

 veris filius. So likewise Mouffet tells us, that the 

 flea is produced from the dust, especially when 

 moistened with urine, the smallest ones springing 

 from putrid matter; and Scaliger relates that they 

 are produced from the moistened humours among 

 the hairs of dogs. 



The Dutch naturalist Leeuwenhoeck was, how- 



* Our English name Flea, and the German Flock, are evi- 

 dently deduced from the q.uick motions of this insect. 



