OTITIS EXTERNA. 197 
wallsof that passage appear as though fine coal-dust had been sprinkled over 
them. 
If simple treatment is promptly applied, in many instances a speedy cure of 
the commoner forms of otitis externa can be effected; but if delayed the affec- 
tion is likely to prove obstinate, deep and important structures becoming involved. 
Once the passage is thoroughly inflamed, recovery will generally be slow, and 
there is liability of ulceration occurring in its cutaneous lining and cartilages. 
After the disease of the external ear becomes established in the passage, as far 
as can be seen it will appear to have a brownish coating. This collection is at 
first pasty, but in time may thicken, and if there is much inflammation it dries and 
forms crusts. If ulceration occurs, there is quite a copious discharge, which is 
at first a muddy brcwn, and after a time yellowish. 
With the occurrence of the brownish coating there is an unnatural odor, 
which generally becomes highly offensive; and this constitutes a positive sign 
that the passage is quite seriously ulcerated, or the drum membrane is ruptured 
and the parts beyond are diseased. 
A thick, yellowish discharge, — of what is commonly called matter — appears 
only in a very small proportion of cases, and in these there is either abscess, 
ulceration, or disease of the bones or cartilages; or the drum membrane has 
been ruptured and the discharge is from the middle ear. 
The intensity of the symptoms, — shaking the head, scratching at the ear, 
and other signs of distress — are seldom in proportion to the existing disease. 
For instance, a dog may present them in violent form and yet have merely a 
mild and trifling irritation of the ear-flap; whereas another may suffer from seri- 
ous inflammation or ulceration deep within the passage, the same having existed 
for a long time, and these symptoms be far less pronounced. However, in the 
latter the shaking of the head is generally more constant and occurs every few 
moments, and the head is often turned to the affected side. 
This disease is usually unilateral, that is, in one ear only, although both ears 
are, of course, sometimes affected; but this is never likely except in cases of 
very long standing. 
An accumulation of the natural secretion of the ear, if excessive, causes feel- 
ings of discomfort, with consequent shaking of the head, but there are no signs 
of inflammation to be detected, nor does any exist from this cause alone. Con- 
sequently such trouble cannot rightly be included under this head, but for 
convenience this mention is made. 
When the passage and drum membrane are not involved in the inflamma- 
tion the hearing-power is not affected except where the ear passage is blocked 
by “wax” or some foreign body, or the drum membrane covered in a similar 
way by a vegetable parasite ; and an ear passage may even be inflamed without 
deafness resulting if not closed by the accompanying swelling. But in cases in 
which the inflammation is deep within the canal or there is ulceration, or the 
