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though it were only a particle of his own excrement adhering to the 

 glals, he can, by a touch only of one claw, cling to it. 



Now if we reflect on this wonderful and complicated formation 

 of joints in a Flea's leg, we Ihall ceafe \vondering that it can leap 

 to fo great a height as we fee ; nor alk the quellion (which I have 

 often had put to me) whether Fleas had wings to carry them fo far 

 and high? 



Farther, I cut a maggot, produced from the Flea's egg, and was 

 almoll full grown, into two pieces, and placed each part before a 

 microfcope of the fame magnifying power as that by which the 

 maggot newly hatched was drawn : but if I had placed the maggot 

 entire before the microfcope it would have been impoffible, by 

 reafon of its continual motion, for the limner to have given a true 

 figure of it. 



Fig. 21. A B C D, reprefents the head and three firft joints of 

 this maggot's body : I had placed it upright before the microfcope, 

 but before the limner had got it, the head was inclined downwards, 

 as fhewn at ABC; nevertheless this piece of a. maggot, for the 

 fpace of an hour, moved itfelf, and often lifted up the head. 



Fig. 22. E F G reprefents the four latl joints of the maggot, con- 

 ftituting its hind part, in which not only may plainly be fcen, at 

 F, the organs or limbs with which the tail of this maggot is pro- 

 vided, but the place may alfo be dillinguifhcd where the excre- 

 ments are voided. 



Now this maggot not being provided wnfh any limbs or organs 

 for moving from place to place, except what are feen in ^g. 21, at 

 D, in its head ; and in Jig. 22, as F. in its tail : the many hairs it 

 has on its body are a great help to its motion ; but, at the fame 

 time, are a very great hindrance to it, if it meets with any liquid, 

 mattei". So that even the hundredth part of the liquid excrement 

 voided by the Flea at one time, is fufficient not only to adhere to 

 thofe hairs on the maggot, fo as to Hop its progrefs, but ahb to 

 kill the maggot itfelf, by reafon that it is not able to extricate itfelf; 

 from the moillure : therefore, as we see how little able thefe mag- 



