IMPROVED. roi 



The third, is term'd the Cornea or horny Coat : 5^. Cornea. 

 It has a greater Convexity than the reft of the 

 Globe of the Eye, and is compofed of feveral paral- 

 lel Latnitite, which are nourilhed by man^ Blood- 

 VefTels fo exceeding fine, as not even to hinder the 

 fnialleft Rays of Light from entering the Eye. And 

 it has fo exquifite a Senfe, that, upon the leaft Touchy 

 the Tears might be fqueezed out of the Lachrymal The Ufe oi: 

 Gla}i(i, to wafti off any Filth, which by fticking to Tears, 

 the Cornea, miglit render it opaque and dark. 



The fourth, is called Choroides ; it lies under the^ith. Cho- 

 Sclerotica, and is much thinner than that. Anato- rc-i-^^s. 

 mills think that this arifes from the Pia Mater or 

 thin cob-web-covering- of the Brain, which is ex- 

 panded all along the Infide of the Optick Nerve, 

 and terminates in the Choroides. On the Infide of 

 this Membrane is a kind of blackifh Subftance, 

 prepared by Nature, and fpread over the back Part 

 of the Eye. This Coat has a great Number of 

 Blood-Vefiels, which come from the fecond called 

 Sclerotica. The Choroides itfelf is of a whitiih Co- Its Colour 

 lour, only the Glands thereabouts feparate fuch 

 blackifh Matter as is before fpoken of. Mr. S?h7f'C Mr. 5n,;f'^'s 

 fays, that fuch Matter as is fpread over the Infide '>^'^^V"J,/'^ 

 of this Membrane, is for the End that the Idea's ifh^Mp^n^r 

 received into the Eye might appear more iliuftri-fnrfad'ui.on 

 ous ; but this is a dark Saying, like many more Ex- the c ho- 

 prefiions made ufe of by thofe who have treated "oi^^^^^^- 

 upon the Subje(5l of Farriery. 



There is no Doubt, but iuch blackifh Glaze, or'^^'-V^'-' 

 vifcous Liquor, is fpread over the Infide of this*^/^^ ' ^ f' ' 

 Membrane, to the End that the Rays of Light, cbnjr.g ic. 

 which pafs from Objefts into the Eye, may not be 

 reflefted back again, but (as it were) become tho- 

 roughly imbibed, and have a due Weight an.d Force 

 upon the fixth Coat called the Retina. The Pupil- 



The Choroides is open, or has a round Hole be-^^- wbac. 

 fore (for the PafFage of the Rays of Light,) called ^^[''^'^^J' 

 Pupi/la ; and by the common People, ( though very l^^^r ol 

 abfurJly, ) the Sight of the Eye. \h^ Eye 



F 3 The 



