SECTION VII. 
DISEASES OF THE EARS. 
CHAPTER I. 
GENERAL CONSIDERATIONS. 
Ir is not surprising that the term “canker ” is still employed for almost every 
affection of the ear, since traditional names applied to diseases by the laity 
continue to be used even after they have long been proved indefinite, vague, 
and inappropriate. 
If a dog shakes his head and scratches the side of it occasionally for a day 
or two he is said to have this disease, whether his ears are affected superficially, 
from a slight irritation of the skin, or internally, from severe inflammation. 
When the hearing apparatus was a thing of mystery this was perhaps pardon- 
able; but at the present time it is certainly not so, and the term canker should 
be obsolete. 
In order to avoid confusion and make clear the purpose of the writer, the 
discussion of the anatomy and physiology of the ear will be omitted, and only 
a brief description of the essential parts of the hearing apparatus considered. 
These, divided broadly, are respectively the external, middle and internal ears. 
The external ear comprises not only that outer portion which can be grasped 
with the hand, which is the auricle, but also the canal or passage leading inward. 
This passage ends at the drum membrane, which constitutes the dividing line 
between the external and middle ears. 
The middle ear is situated at the bottom of the auditory canal, and includes 
the drum membrane and the little bones or ossicles which are to be found in the 
drum cavity or tympanum. 
In conformity with the rule distinguishing inflammatory aieedus by the 
suffix zfs, general inflammation of the ear becomes otitis; and to this can be 
added terms to designate the particular localities and structures affected. Thus, 
inflammation of the external ear may rightly be otitis externa, that of the mid- 
dle ear, otitis media, and of the internal ear, otitis interna. But the internal ear 
rarely alone suffers from inflammation, and as a rule, if not invariably, where it 
exists it is but an extension of like trouble in the middle ear; therefore it is 
194 
