B4 The Carrier's New Guide. Ch. XXIV. 



" which Difeafe the Animal we are treating of is much 

 " fubjeft to, though we have not fo proper a Term for 

 *' it as this is. 



But a late eminent Phyfician has obferved, that thefe 

 Reprefentations cannot be occaiioned by any Kind of Mat- 

 ter floating m the waiery Humour, becaufe the Pofition of 

 the Retina, and Convexity of the Cornea is fuch, that all 

 Bodies mull be placed at a greater Dillance from the Eye 

 than the aqueous Humour, or the Cornea, to caufe fuch 

 Appearances ; and therefore he fays, thole Signs can only 

 be exhibited, when the Parts of the Retina are over-much 

 comprefl'ed by a Diftention of the Arteries. And this may 

 jiG tta'Se- happen, and is oftentimes the Caufe of a 

 j.pjj^_ Gutta Serena, which is the laft Sort of 



Blindnefs which we mentioned, viz. where 

 the Eye feems to have no vifiblc Defed in it. And there- 

 fore, as that Author has obferved, whenever thofe Signs 

 appear with a Cataradl, any fuch Catarad muft at the 

 fame time be accompanied with a Gutia Serena ; for a Gut- 

 ia Serena is often the Concomitant of other Difeafes of the 

 Eyes, but is only diftinguilhable as fuch, when the Cornea 

 and Humours are tranfparent. 



*rke Shns Now I am apt to believe, there are but 



•^ * very (ew who have bought many Horfes, 



and have not had Experience of this Sort of Blindnefs 

 to their Coft. And the Signs that Mr. Snape has attributed 

 to a Catarad, when a Horfe Harts with his Head, if that 

 is not the Etfedt of Fear, it is, no doubt, to be lufpedted 

 as a Token of bad Eyes, and to denote that Imperfedf ion 

 which we are now treating of : But there is one, which is 

 the moft infallible, and more to be depended on than any 

 oihcr, viz. When a Horfe moves his Ears backwards and 

 forwards, and often points them towards his Eyes, as if 

 he wanted to drive away Flies, when there are none near 

 him : And if he renew his fhaking of his Ears, as often as 

 he is turned to a new and different Light, it may be then 

 with very good Reafon fufpeded, his Eyes are defedive, 

 though nothing appears outwardly upon them ; and this I 

 have oftentimes obferv'd in Horfes that wereill-fighted, and 

 have known it fometimes the Fore-runner of abfolute Blind- 

 nefs. 



Thefe being the Signs of a Gutta Seiena, and the imme- 

 diate Caufe being a Diftenrion of the fmall Arteries prcfhng 

 upon fcveral Parts of the Retina, as was obferv'd j what- 

 ever 



