IMPROVED. 117 



keep the Globe turgid and full. I fay, the Comea ns in young 

 in old Age becomes flatter or lefs Convex, and this °"^'^- 

 is to be helped by the Ule of Convex Spedlacles on- 

 ly ,• and thefe are to be fitted according to the Decay 

 of the Eye, or Flatnefs of the Cornea ; for I do not 

 allow that fo much defends upon the other Parts of 

 the Eye, as on the Cryitalline Humour's growing 

 plainer and of a lefier Sphere, according as a Perfon 

 advances in Years ; no, I am well fatisfied that the 

 Qornea or horny Coat (which is the outermofl Part Caufe of 

 of the Eye before) is moftly the Caufe of Dimnefs Dimnefs of 

 of Sight, and no doubt but it is the fame in Horfes : ^^ ^• 

 For in them I have obferved the Cornea become \yj,y q\,\ 

 more fiat or lefs Convex as they grew old ; but this Hori'cs lee 

 Creature is not fo fubje6l to the Inlirmity I am now '•'^oviii than 

 treating of as Man, by reafon they do not live to /"^^"S 

 half the Age. And though it may be faid in gene- 

 ral, that a Horfe is as old at Seven, as a Man is at 

 Forty, yet his Eyes (if he is well kept) may conti- 

 nue jfull, and the Cornea be kept prominent till he 

 is Sixteen, or even Twenty Years of Age. Befides, ■ 

 Mankind are fo carelefs of this ineftimable BlelTing, 

 that they little regard the Value of it, till it is often 

 too late; for they do their Eyes a vaA deal of Da- Fire pemi- 

 mage by fitting near and facing hot glaring Fires, clous to the 

 infomuch, that they, in fomie Meafure, parboil the ^^'^' 

 Cryflalline Humour in particular, as well as, do 

 Hurt to the reft of the Parts within the Globe of the , 

 Eye. But as the Cryftalline Humour is (as I have 

 fnid before) of the moil foHd Confiftence of any of 

 the three Humours of tlie Eye ; therefore lefs Heat 

 is neceffary to make it of fuch a Nature, as that the 

 Rays of Light cannot pafs through it, fo as to make 

 Vifion diftin6l. And in fuch Cafe, the outermoll 

 Lamina or Covering mufl be turned off by a Needle, 

 as in the Operation for the Glaucoma or Cataraft. 



Another Thing is Candle- Light, and of this Peo- Candle- 

 ple generally fufter themfelves to have too much ^'f ^^' 

 when there is little Occafion for it. And by how by'^J'^ ^ad 

 much the more we accuftom our felves to it, or for the 



read Eyes. 



