52 GENERAL ANAESTHESIA. 



circulation are accelerated. This stage sometimes lasts for ten 

 minutes, and is succeeded by that of surgical anaesthesia. 



The quantity of ether used is often considerable, from ten to 

 twenty fluid ounces, sometimes even more. Recovery is slower than 

 after chloroform. 



Though less dangerous than chloroform, ether is not, as some 

 suggest, absolutely innocent, and has claimed a number of victims 

 in human surgery. Nevertheless Gurlt's statistics show the mortality 

 from chloroform to be fifteen times greater than that from ether. 



Anaesthesia can be produced by the introduction of ether vapour 

 into the rectum. It was tried first on animals by Dupuy and 

 Thiernesse, and has been recommended by Cagny for the purpose 

 of producing a certain degree of drowsiness in horses to facilitate 

 casting or to permit of trifling operations in the standing position. 

 The method is simple ; a flask or tube with a narrow neck is 

 partially filled with ether ; one end of a rubber tube is slipped over 

 the neck, and the other end introduced into the rectum. The flask 

 is placed in water heated to 120° F. Ether vapour is at once given 

 off, enters the rectum, and is absorbed by the mucous membrane. 

 One and a half to two ounces of ether are sufficient. Experience 

 does not show this method to have any marked advantages. In 

 place of partial anaesthesia active excitation often follows. Such 

 violent expulsive efforts are sometimes made as to produce rectal 

 prolapse. In man cyanosis, collapse, and even a kind of asphyxia 

 have resulted. The uncertainty and serious inconvenience of this 

 method have prevented its being commonly adopted. Mixed anaes- 

 thesia, produced by the injection into the rectum of ether vapour, 

 and preceded by the subcutaneous administration of morphine and 

 chloral, is slow in its effects and of little practical utility. 



In English human surgery a favourite method is to obtain anaes- 

 thesia with nitrous oxide and maintain it with ether. The method 

 has many advantages, and has come largely into use. 



Chloral is usually injected intra-venously, alone or after hypo- 

 dermic injection of morphine. Intra-venous injection of 20 per cent, 

 solutions produces very rapid and complete anaesthesia. Though 

 declared dangerous by human surgeons, this method has been recom- 

 mended in France and Denmark for the horse, on account of the 

 ease with which injections can be made into the jugular. The 

 injection, which may be of any strength between 10 and 20 per cent., 

 must be freshly prepared, and the best vehicle is physiological saline 

 solution. 



Intra-venous injection requires very special precautions. The 



