(614)
Owners were very apt to stumble in the day-time, if it were bright and Sun-shine, but travell'd very well and securely in the evening, and in dark, cloudy weather.
What the cause may be of that fungous Excrescence, or why Horses are peculiarly obnoxious to it, or what kind of Horses most, I have not considered. But, I cannot think, it comes from (training in great draughts and races, or from hard travel, because I have seen very large Spunges (as I may call them) in young Horses eyes of 2 and 4 years old, before they were backed; which, after they have been taken up from Grass, and kept with dry meat, have very much abated, and afterwards being turn'd to grass in the Spring to cleanse and cool their bodies, have increased again to the wonted bigness. But whether it were from their moist Feeding, or holding down their heads to eat (whereby there might be a greater deflux of humours to that part) I cannot determine. But for as much as there are few Horses quite free from this evil, and many render'd very inconsiderable by it, I will recount the most remarkable Cases, which make Horses most useless and suspected.
1. The more and greater those Excrescences are, the more the pupil of the Eye or the Sight is in danger of being quite obstructed; which you may farther examine by turning the Horses eye to the light, and observing how much of the pupil they do obstruct.
2. These Spunges on the upper edge of the Uvea are apt to grow the largest, and hinder the Sight most.
3. That which grows on the middle of the Uvea, does more hinder the fight by diffracting the Object, than that, which grows in either Corner or Angle of it.
As for the Cure, I suppose there can be none expected, but from a drying kind of diet; though perhaps outwardly something may be devised to shadow the Eyes, and keep them from being nakedly expo&d to the Sun, whereby the pupil will not be so closely contracted, and consequently the Sight not so much obstructed.
