l8 TREPHINING OF THE FACIAL SINUSES. 



skin must be moved and disturbed each time causing pain 

 and inviting infection. The question of pain must always 

 be seriously considered as it not only affects the time re- 

 quired for dressing and its efficacy, but has an important 

 relation to the docility of the animal after recovery, some 

 horses having their dispositions permanently ruined by the 

 irritation due to the oft repeated painful dressing of wounds. 



The cicatricial contraction of the tissues of the horse is 

 so great that the removal of a circular disk of skin ^ to i )^ 

 in. in diameter on the face does not leave a visible scar 

 so that the question of blemish falls back upon that of in- 

 fection, which, as we have asserted above is far more 

 probable by the European method. 



The rapidity and certanity of recovery are dependent 

 upon the considerations above discussed. The removal of 

 the cutaneous disk is certainly easier and quicker than the 

 other method. The convenience for dressing is evidently 

 superior by the Knglish and American method. 



The opening of the maxillary sinuses into the nostrils is 

 based upon the surgical principle that suppurating cavities 

 should be provided with ample drainage from the most 

 dependent part. The direction to leave the external wound 

 open, at first thought seems antagonistic to general surgical 

 principles but it should be remembered that the wound 

 consists only of the incision through the skin, connective 

 tissue and bone, and that any plug which we can put in 

 this opening can only serve to dam back the secretions of 

 the cavity and can not prevent it from corning in contact 

 with the wounded surface. It must further be regarded 

 that the respiratory mucosa of the upper air passages are 

 not irritated or injured in any manner so far as we can ob- 

 serve clinically by the direct admission of air into them 

 through a trephine, or other artificial opening, but on the 

 contrary the suppuration in a sinus is constantly aggravated 

 by the retention of the pus and exclusion of air and re- 

 covery facilitated by thorough drainage and aeration. 



