( ^38 ) 



not a watery fiibftancc, but rather a kind of pellucid nuifcle ; but, 

 iiotwitlidanding all my endeavours, I could not form any determi- 

 nate or certain judgment on this head, becaufe the fubllancc of this 

 vitreous humour, always changed into a kind of v.atery matter. 



Moreover, I examined the eyes of fifhes ; thefe are i^erfeflly 

 fpherical, and I found, tiiat they confilted of the fame kind of thin 

 coats or fcales, laid one on another, as I have defcribed the eyes of 

 animals to be formed ; each coat or fcale, was alfo compofed of 

 lilaments, but, thefe filaments have not th.at kind of bending courfe, as 

 in animals; and, with all my endeavours, I could not difcover in 

 what direction tliey were jilaced ; for, where the filaments draw 

 towards a point or center, they are fo exceedingly llender, and cohere 

 lb clofely, that they efcape the fight, and caufe fuch a confufion of 

 objecls, that I cannot be certain, whether they terminate in that center, 

 or return back again from it. Fig. 6, ABC D, reprefents the cryftal- 

 line humour or fubftance in the eye of a cod-filh ; and, though I 

 drew the lines, here made to reprefent the filaments, from the center 

 or point A, to the center or point C, with only a pair of compalTes, 

 wider apart than in the other figures, yet the filaments which 

 compofe thefe fcales or coats, are not in faft thicker, except in the 

 middle at B and D, and the nearer they approach the point A or C 

 the thinner they are. Fig. 7, ihews the natural fize of the cryflal- 

 line humour in this eye. 



I alfo examined the cryftalline humour in the eyes of birds, only 

 to fee how the filaments compofing their coats or fcales, took their 

 courie ; and, at length, after many obfervations, 1 found the filaments, 

 in the eye of a turkey, to take the fame direction, as thole in fiihes : 

 but whereas the cryftalline humour in tlie eyes of fifties is perfeftly 

 round, that in the eyes of birds, is flattened, as at^^'-. 8, bing with its 

 flat fide D, next the tunica cornea or horny coat of the eye. And, up- 

 f^n my cutting with a flijarp knife many pieces of the fcales or coats 



