CHAPTER III. 



THE ADMINISTRATION OF AN^ffiSTHETICS (LOCAL 

 AND GENERAL). 



General Remarks. — Anaesthetics are medicinal agents which 

 produce unconsciousness to pain, and they are used for this 

 purpose very largely when performing operations. They are of 

 very great value on humane grounds, and also on account of 

 the convenience they afford to the operator. They cause 

 relaxation of muscular tissues in some cases (such as hernise), 

 and allow delicate operations to be conducted with much 

 greater care and precision, when the animal is perfectly still, 

 than could be adopted with a struggling, violent patient. They 

 are divided into two classes, viz., local and general. 



By the term " local " anaesthetic is understood " an agent 

 which removes sensation from the parts to which, or contiguous 

 to which, it is applied." 



Under this heading, for surgical use, come such agents as cold 

 water, ice, ether, ethyl-chloride, cocaine, eucaine, holocaine, and 

 orthoform. 



By the term " general " anaesthetic is understood " a medicinal 

 agent which acts upon the higher centres to produce a com- 

 plete loss of consciousness in the whole body of the animal to 

 which it is administered." 



Under this heading, for surgical use, come such preparations 

 as chloroform, ether, the A.C.E. and other mixtures. 



Local Anaesthetics. — Taking the local anaesthetics first, anaes- 

 thesia produced by the first four_ agents mentioned (viz., cold 



