GENERAL ANyESTHESIA. 



51 



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 anaesthetic, but is infinitel}' 

 safer. 



Fig. 67. — Clix's chloroform muzzle 



Fig. Q-ja. — Arnold's modified Carlisle 

 chloroform muzzle. 



Surgical An.esthesia by Chloroform. — Chloroform is usually 

 administered as follows : — Food having, if possible, been withheld 

 for twelve hours, the horse is cast, and girths or other impedi- 

 ments 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 ancesthesia 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 b}^ 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 



