66 Surgical Diseases and Surgery of the Dog 



ear-speculum should always be inserted while the cautery is in 

 use, partly for the purpose of dilating the canal, but also to protect 

 adjacent parts. A day or two later a mass of resultant necrotic 

 tissue needs to be removed with forceps and irrigation. Subsequent 

 treatment consists in irrigation with antiseptic solutions, thorough 

 drying with absorbent cotton, and insufflation or packing with ab- 

 sorbent powders, such as xeroform, aristol, etc. Any sluggishness 

 in healing or tendency towards unnatural secretion should be treated 

 with injections of silver solution in the strength employed in 

 otorrhea. 



Extensive cutting or burning of the canal involving re- 

 moval or destruction of all or most of the integument leads to oblit- 

 eration of the canal. It will be remembered that it is the epithelium 

 of the free surface of the body which prevents union of contiguous 

 parts. When a raw surface, denuded of all epithelium, is brought 

 in contact with another similar surface, union of the two takes place 

 by interformation of connective tissue. Even a deep sac-like 

 wound fills up with reparative tissue, because the latter grows more 

 quickly than does the epithelium from the neighboring surface. If 

 the epithelium were the quicker to grow, it would extend over the 

 wounded surface, prevent the filling-up process, and lead to the for- 

 mation of pits and depressions in all wounds deeper than the skin. 

 And it is exactly this process of connective-tissue reparation which 

 tends to develop as a consequence of radical surgical measures af- 

 fecting the external auditory canal. A free granulating surface is 

 left, which fills up and coalesces and completely obliterates the 

 canal. The indications in these cases are daily irrigation of the 

 parts and packing with gauze impregnated with dessicant powders, 

 until the epithelium has had time to spread inwards over the raw 

 surface to the depths of the canal. A case presenting complete 

 obliteration of both canals following excesssive ablation of the parts, 

 and which I endeavored to remedy by making an artificial opening 

 and canal, terminated in failure after a four months' attempt at 

 keeping it open. Strangely enough the hearing of the animal seemed 

 very little impaired, which suggests that this result is not to be re- 

 garded as altogether undesirable since it certainly protects from 

 future troubles of a like nature. 



Hematoma. This lesion is characterized by rupture of ves- 

 sels and an extravasation of blood or hemorrhagic exudate beneath 



