( loS ) 



At fg. 10, TV, is feeii this artery, ^vhicll was wounded a little 

 above V. The letters V and X indicate the extravafated blood. V 

 W denote the minute artery in which the blood purfued its regular 

 courfe, though clofe to the place, at P, it ill'ued out from the artery 

 TV. 



This fight at firft furprized me, but my wonder ceafed when I 

 obfcrved that tiiis blood vellel V W, was united with a large one at 

 W, and of that fort whicii, carrying back the blood to the heart, is 

 called a vein. And by means of this laft-mentioned velTel, the blood 

 was carried through the paflage V W, as it were, by a kind of fuc- 

 tion, with as much Iwiftnefs as it had been before driven from T to 

 V, infomuch that I was perfuaded, that if the fniall velTel V had not 

 been united to the artery T V, but ojily its orifice liad laid in the 

 extravafated blood, about the fpot at V, that fuch extravafated blood 

 would in a ihort time have been, as I may fay, fucked up and car- 

 ried away with the remainder of the blood towards W. 



I have often reflefted on the nature of thofe very thin tranfparent 

 pellicles, or (kins, which conftitute the wings of fmall flying infedls, 

 fuch as gnats, flies, moths, and the like ; fome of which I have 

 obferved to be entirely covered witii feathers, others compofed only 

 of thofe mufcular parts which flrengthen and expand tlie wing, and 

 others arc wholly covered with hairs : and when I confidercd, tliat 

 thcfe hairs, or feathers, are fixed or rooted in regular order in the 

 membrane of the wing, my thoughts were wholly bent to difcover 

 how thefe wings might be formed. 



As to the fuppofition which at firft occured, that thefe membranes 

 were compofed of a tranfparent vifcous or gummy matter, congealed 

 or hardened to a due confiflence, I could not fatisfy myfelf with 

 that idea, for it feemed impoffible to me, that in that cafe the feathers 

 and hairs could be produced in fuch regular order ; and yet, it was 

 beyond my compreiienfion how fo thin a membrane could be furnifli- 



