386 INFLAMMATIONS. 
Cataract may be known by a whiteness, more or less marked, in 
the pupil, and evidently beneath the surface of the eye, the disease 
consisting in an opacity of the lens, which is situated behind the 
pupil. It may occur from a blow, or as the result of inflammation, 
or from hereditary tendency. No treatment is of any use. 
In amaurosis the eye looks clear, and there is no inflammation ; 
but the nerve is destroyed, and there is partial or total blindness. 
It may be known by the great size of the pupil. 
CANKER, OR INFLAMMATION OF THE EAR. 
From high feeding generally and exposure to the weather 
many dogs (especially of a sporting kind) contract an inflamma- 
tion of the membrane or skin lining the ear. This produces irri- 
tation, and the dog shakes his head continually, which, together 
with the tendency to spread externally, causes an ulceration of the 
tips of the ears of those dogs, such as the hound, pointer, setter, 
spaniel, &c., which have these organs long and pendulous. Hénce 
the superficial observer is apt to confine his observation to this 
external ulceration, and I have even known the tips of the ears 
cut off in the hope of getting rid of the mischief, whereas it was 
only aggravated, because the incessant shaking caused the wound 
to extend, while the internal mischief was not in the slightest 
degree relieved. The pointer is particularly liable to “ canker,” 
as shown on the tips of the ears, because he has little hair on this 
part to take off the acuteness of the “smack” which is given in 
the shaking of the head, Long-haired dogs, on the other hand, 
are quite as liable to the real disease, as evidenced on an examina- 
tion of the internal surface, but from the protection afforded by 
the hair, the pendulous ear is not so much ulcerated or inflamed. 
Whenever, therefore, a dog is seen to be continually shaking his 
head and abortively trying to rub or scratch his ear, not being 
able to succeed because he cannot reach the interior, an examina- 
tion should be made of the passage leading into the head; and if 
the lining is red and inflamed, there is clear evidence of the disease, 
even if the external ear is altogether free from it. On the other 
hand, the mere existence of an ulceration on the tips of the ears is 
no absolute proof of “canker,” because it may have been caused by 
