BLINDNESS. 235 



SECTION XVII. 



BLINDNESS. 



Sheep are more subject to diseases of the eye that lead on to blind- 

 ness than many persons who are most accustomed to them imagine. 

 It is a singular circumstance, and not so well known as it ought to be, 

 that if the eyes of a flock of sheep are carefully examined, half of 

 them will exhibit either disease then present, or indications of that 

 which existed at no very distant date. 



Inflammation of the eye, which constitutes the commencement of 

 the disease, may arise from various causes. Sheep driven fast to a 

 distant market have suddenly become blind ; those who have been 

 chased about by dogs, have at no great distance of time lost their 

 sight, and especially if, in both cases, they were afterwards exposed 

 in°a damp and bleak situation. The violent driving, while it produced 

 fever, determined an undue quantity of blood to the head : it pressed, 

 or perhaps was effused upon the origins of the nerves of the eye ; and 

 the after neglect confirmed the fever, and aggravated the mischief. 



At other times, this seems to be an epidemic complaint. The 

 greater part of the flock is suddenly afflicted with sore and inflamed 

 eyes, and particularly at the latter end of the year, and when the 

 weather has been variable, yet cold and moist. Some have thought 

 that this complaint is infectious, but it is at least epidemic. A white 

 film gradually spreads over the eyes, which the animal generally 

 keeps closed, while at first a watery fluid, and afterwards a thicker 

 mucous matter, is discharged from them. The film increases until 

 the whole of the eye is of a pearly whiteness. If proper means are 

 adopted, and often if nothing is done, inflammation abates, and the 

 eye begins to clear, usually commencing at the upper part of the eye, 

 and gradually proceeding downward until the whole of the organ is 

 once more transparent, with the exception, perhaps, of a diminutive 

 spot or two, or a discoloration of part of the iris. Many of the sheep, 

 however, do not perfectly recover the sight of both eyes, and some 

 remain totally blind, either from the continuance of the opacity, or 

 that, while the eye becomes clear, the optic nerve is palsied, the pupil 

 does not dilate, and there is gutta serena. 



The first thing to be done is to bleed from the vein at the corner of 

 the eye. There'will be the double advantage of bleeding generally, 

 and of drawing blood from the inflamed part. The shepherd should 

 take the sheep between his knees, and then, placing the animal with 

 his rump against the wall, he will have full com.mand of him. If he 

 now presses upon tlie vein with his left hand, about two inches frorn 

 the angle of the jaw, and opposite to the third grinder, he will see it 

 rise as it descends from the corner of the eye, and runs along the 

 cheek. He should puncture it about an inch or rather less from the 

 eye. Some shepherds recommend that the blood should be suffered 



