( 71 ) 



be underftood, that tlie fame obtains in the fmalleli:, and which I 

 have {i^€n in the dillecflion of common flies. 



At the time the Hmner was making thefe drawings, I took a 

 fmall Gnat of that fort which is not troublefome to us, having no 

 (ling : the head of this Gnat I cut off, in order to extradl its optic 

 ner\^es, but I could not, after feveral trials, fee them dillinftly. 

 While I was busied in this attempt, I frequently faw the brain in 

 the Gnat's head fin-rounded with a great many veffels, which I 

 judged to be blood veffels : and though it fhould feem fcareely pof- 

 fible to extrad; the brain from this creature's head, M-ithout dellro^'ing 

 the texture of the brain and its veffels, yet, I at length fucceeded to 

 my wiffi, and, without their being much injured, placed the ^^•hole 

 before the microfcope ; this I delivered to the limner, that he might 

 make a drawing of it, and the rather, as I had been told by a gentle- 

 man of eminence, that a certain perfon, whenever my difcoveries 

 were the fubjeft of converfation, was accuffomed to fay, that the 

 experiments stated by me could not poffibly be performed ; becaufe 

 (as that fame perfon pretended), the inffruments ufed by me, how- 

 ever exquifitely conftrufted, could not be at all capable of perform- 

 ing the dilTedlions I defcribed. But I little regard thefe malevolent 

 infinuations of mankind, and perhaps this very perfon is one of thofe 

 who would be glad, if he was able to perform the like operations. 



Fig. 5, RST, reprefents the brain taken out of the head of this 

 Gnat, and alfo the velfels, which in part furround it, and in part 

 pervade the fubftance of it, as nearly as the limner could follow 

 them in his drawing ; for while he was employed about it, he fre- 

 quently declared that he could by no means reprefent in the draw- 

 ing all the veffels which he faw. 



The flies before mentioned, have the extremities of their feet cover- 

 ed with an incredible number of hairy parts, by the help of which 

 they are better able than other flies to climb up a glafs though it be 

 ever fo free from impurities or irregularities, of which they might 

 take hold. I have therefore often placed the feet of thofe flies before 



