70 CANINE AND FELINE SURGERY. 



Tapping the Cornea- — -This operation is very useful in some 

 cases of staphyloma and ulceration of the cornea where healing 

 is prolonged. It is very simple, and, if done carefully under 

 aseptic precautions, need give rise to no bad results ; the object 

 is to relieve the tension produced on the cornea by the aqueous 

 humour, and to thus facilitate the commencement of the healing 

 process. It may have to be done two or three times at short 

 intervals. After the thorough application of cocaine or eucaine 

 solution and some solution of boracic acid or chinosol as an 

 antiseptic, the patient's head is held firmly by an assistant and 

 the lids forced gently apart by the forefinger and thumb or by 



Fie. 41. 

 Eye speculum (Bowman's). 



a speculum. The operator then plunges a bayonet-pointed or 

 broad-bladed needle through the cornea at its outer margin, 

 and, whilst the thin part of the blade of the needle is in the 

 wound, applies gentle pressure upon the eyeball so as to force 

 out a quantity of the aqueous humour. The needle is with- 

 drawn, and the cornea carefully wiped with boric acid solution. 

 Care must be taken to keep the needle in a direction 

 approximately parallel with the cornea and to avoid injuring 

 the other side of the eyeball, the lens, or the iris. 



Operation for Staphyloma.— Staphyloma of the cornea is 

 sometimes conveniently treated by ligature of the protruding 

 portion. For this purpose a very fine thread of silk is passed 



