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" the figure of the parts entire ; a circumftance which accounts for 

 " the difagreement we find among anatomifis. 



" Of the Coats of the Eye. 



" The eye is compofed externally of three coats, or teguments, 

 " one covering the other, and forming a ball perfe<511y globular, ex- 

 " cept at the fore part, whicli is a little more protuberant than the 

 " reft ; within this ball are three different fubftances called humours. 



" The firft, or outer coat, is called the fclerotica ; the fecond, or 

 " middle one, is called the choroides ; the interior one is named the 

 " retina. 



" Sclerotica. Cor?iea. 



" The exterior membrane, which inclofes and covers the whole eye, 

 " is called the fclerotica and cornea ; it is, however, ftrictly fpeak- 

 " ing, but one and the fame membrane, with different names appro- 

 " priated to different parts : the hinder and opake part being more 

 " generally denominated the fclerotica, the fore and tranfparent part 

 " the cornea. 



♦' The fclerotica is hard, elaftic, of a white colour, refembling a kind 

 " of parchment ; the hinder part is very thick and opake, but 

 " it grows gradually thinner as it advances towards the part where 

 " the white of the eye terminates. The fore part is thinner, and 

 " tranfparent ; it is alfo more protuberant and convex than the reft 

 " of the eye, appearing like a fegment af a fmall fphere applied to 

 " a larger, and is called cornea, from its tranfparency. The cornea 

 " is thick, ftrong, and- infenfible ; its tranfparency is neceffary for 

 " the free admiilion of the light. This membrane is compofed of fe- 

 " veral plates, laid one over the other, repleniflie .1 with a clear 

 "water, and pellucid veffels; thefe plates are moi-e evidently dif- 

 " tin6l in the fore than the hinder part. The fclerotica is embraced; 



