SURC41CAL ANAESTHESIA. 47 



of Dr. Clarke's apparatus are surrounded with an outer metal 

 receiver for containing hot water. 



A simple form of inhaler was suggested by the late J. Roalfe Cox, 

 F.R.C.V.S. It consisted of a leather tube covered with stout canvas, 

 which could be drawn together at either end by a strong drawstring. 

 The tube was slipped over the animal's nostrils and into its mouth, 

 the drawstring tightened and attached to the halter. A sponge 

 saturated with the anaesthetic was then introduced, and the supply 

 of air controlled by regulating the size of the external opening. The 

 Carlisle inhaler is more complicated, but probably not more efficient. 

 It envelops both the upper and lower jaws, thus differing from Cox's, 

 and is provided with a metal sliding sponge-holder on which the 

 chloroform is poured. As sent out it gravely impedes respiration, 

 and for use the writer has modified it by removing the lower solid 

 end, so that the only obstacle between the animal's nostrils and 

 the outer air is the comparatively pervious layer of sponge for 

 receiving the chloroform. Thus altered it uses rather more of the 

 anesthetic, but is infinitely safer. 



Surgical Anaesthesia by Chloroform. Chloroform is usually ad- 

 ministered as follows : — Food having, if possible, been withheld for 

 six hours, the horse is cast, and girths or other impediments to free 

 respiration loosened or removed. During inhalation, attention must 

 be given to the breathing and the pulse. Both are at first accelerated, 

 but later become regular. Unless when using one of the anaesthesia 

 cum asphyxia muzzles, the excitation stage is seldom attended with 

 danger, only lasts a minute or two, and is succeeded by the period 

 of depression. 



The first stage of anaesthesia (excitation) is often accompanied 

 by a peculiar rotary movement of the eye (nystagmus) ; in some 

 animals the eyelids close, opening again when anaesthesia is complete. 

 If, soon after the period of excitement has passed, respiration or 

 circulation becomes impeded, or if respiration be laboured, very 

 rapid, or interrupted, if the pulse be small, frequent, irregular, or 

 intermittent, administration must be stopped. General muscular 

 twitching may also occur, and calls for similar precaution. Rattling 

 in the throat, a serious symptom in man, is of less importance in 

 horses. In the event of its occurring, the tongue should be grasped 

 and drawn forward. Even then the noise does not always cease, 

 being probably due to vibration of the relaxed soft palate, which 

 is set in motion by the 'stream of air passing through the mouth 

 during respiration. 



The loss of sensibility, muscular weakness, character of the pulse 



