252 PRINCIPLES OF VETERINARY SURGERY 



Local anaesthetics are used hypodermically in veterinary 

 subjects. It is seldom used on the mucous membranes ex- 

 cept the conjunctiva; it is seldom applied into the deep 

 structures ; and it cannot be injected intradermically. The 

 skin of animals will not separate to receive an injected 

 liquid. 



An effectual method of anaesthetizing an operating field 

 is to (,i) shave and disinfect the part; (2) inject a dram of 

 the five per cent solution of cocaine, here and there, hy- 

 podermically; and (3) spray the surface thoroughly with 

 ethyl chloride. As the operation proceeds the latter may 

 be sprayed directly into the tissues to carry the anaesthetic 

 state beyond its original extent. 



It is needless to state that injected anesthetics must be 

 aseptic, and the instruments used for its administration 

 absolutely immaculate. Septic liquids and septic syringes 

 cannot be used with impunity in the subcutaneous tissue. 

 The anaesthetic solution must not be exposed to the atmos- 

 phere of the veterinary hospital, the horse stable, or the 

 pharmacy, and each time before the needle of the syringe 

 is inserted into the bottle, it must first be passed through 

 the flame of a match or lamp. The syringe itself requires 

 special care. The all-glass, or the all-steel syringes are 

 preferable, owing to the difficulty of sterilizing the leather 

 plunger of the ordinary hypodermic syringe. 



A mixture of local anaesthetics containing the follow- 

 ing ingredients is also highly recommended for veterinary 

 use: 



I5< Cocaine hydrochlorate grs. iii 



Morphia sulphate grs. iv 



Carbolic acid, 95% TU v 



Sodium chloride grs. iv 



Aqua q. s. ad 5i 



Misce et signa. One dose. 



