CHLOROFOEM. 619 



for human beings, which presents tlie chloroform to the patient in 

 a vapour of easily regulated concentration. The amount of in- 

 fluence the chloroform has over the animal can be ascertained by 

 noting the degree of sensibility his eye manifests when touched 

 by the finger. The best spot to select when doing this, is the inner 

 corner (inner canthus) of the eye on the haw (membrana nictitans). 

 Feel also if the miiscles of the tail offer any resistance to the dock 

 being bent and extended ; and pinch the parts under the tail to 

 still further satisfy the mind. I wish to emphasize the necessity 

 of inducing complete insensibility, when the object is to obtain as 

 much muscular relaxation as possible. Hence, in such a case, 

 abstain from operating until external irritation fails to produce 

 reflex action. If, however, chloroform is given merely to deaden 

 pain, we n©ed not push it so far. After the operation is over, it 

 is well to allow the animal to sleep off the effects of the drug, 

 which he will generally do in about an hour. The hobbles or the 

 apparatus should not be removed until consciousness has returned ; 

 for he is liable to injure himself by struggling when " coming to." 



Russell's chloroform inhaler /consists of a canvas bag provided 

 with a metal bottom into which a tray fitted with sponge can be 

 passed. Having cast the horse (by Mr. Over's method (page 654), 

 or by tying up one fore leg and pulling the head round (page 659), 

 get an assistant to put the inhaler over the horse's muzzle, take 

 out the tray of the inhaler, saturate the sponge with about 1^ oz. 

 of chloroform, return the tray, and proceed to render the animal 

 insensible. When it is necessary to rep'.enish the supply of chloro- 

 form, say, after seven minutes, remove the tray, while retaining 

 the inhaler on the horse's head. ,The supply of air may be easily 

 regulated as necessary. 



It is advisable before giving chloroform to make a subcutaneous 

 injection (p. 644) of 1^ grain of morphine hydrochloride and j^ 

 grain of atropine sulphate (p. 613) in 3 drachms of distilled water; 

 because this injection greatly lessens the excitement, hastens in- 

 sensibility, checks heart failure, and increases the effect of the 

 chloroform, the quantity of which can consequently be reduced. 



Citrine Ointment {Nitrate of Mercury Ointment). 

 See p. 632. 



Cocaine 



is an alkaloid and a very useful agent for producing local insensi- 

 bility to pain. If 5 o.r 6 drops of a solution of 1 grain of hydro- 

 chlorate of cocaine in 20 minims (or dropsi) of water be placed on 

 the surface of the eye, that part will, in from 5 to 10 minutes, lose 



