ETHYL CHLORIDE 167 



OTHER GENERAL ANESTHETICS 



On account of the slow action of ether and the accidents which 

 attend chloroform anesthesia, many substances have been advanced 

 to replace them. Atropine and morphine, and morphine and hyo- 

 scine have been given considerable trial and may do well for opera- 

 tions upon the dog. See morphine scopolamine, p. 182. These 

 preparations are not suitable for the other animals, because they do 

 not produce the characteristic depressant action. Chloral, chlore- 

 tone, etc., give nice results in laboratory animals, but since it is not 

 easy to control the degree of anesthesia, they cannot take the place of 

 chloroform and ether. Of all those advocated, Nitrous Oxide alone 

 has been placed upon a firm base. It is exceedingly successful in 

 short operations and may be administered with oxygen for longer 

 ones. The others are Ethyl Chloride, Ethyl Bromide and Bromo- 

 form. 



Nitrous Oxide. Laughing gas. This is a colorless gas with 

 very slight odor and sweetish taste. It is not inflammable but sup- 

 ports combustion in lighted objects. This gas produces anesthesia in 

 from /4 to three minutes, but has a very short period of action aud- 

 its use was formerly limited to short operations, such as the extrac- 

 tion of teeth of human patients. More recently it has be^n found, 

 that if this gas is mixed with oxygen it may be administered over a 

 long period of time and it is now used by many operators for most 

 operations. Since nitrous oxide does not produce a complete relax- 

 ation of the muscles, ether is sometimes used along with the above 

 mixture for this purpose. This anesthetic has not found much favor 

 in veterinary practice because it is expensive, the apparatus is also 

 expensive and cumbersome, and it is difficult to use because it is not 

 easy to judge the condition of the blood (cyanosis) in veterinary 

 patients. 



iETHYLIS CHLORIDUM — ETHYL CHLORIDE 



This preparation occurs as a highly volatile and infla mm able gas, 

 prepared by the action of hydrochloric acid on absolute alcohol. It 

 condenses to a liquid at about 13° C. (55.4° E.) and is kept in 

 sealed tubes under pressure. These tubes are made with a minute 

 pin-hole nozzle covered with a cap or regulated with a valve, and on 

 opening the valve or removing the cap, the liquid is discharged as a 



fine spray. 



Local Action. On coming in contact with the skin, it evap- 

 orates very rapidly and freezes the tissues so that anesthesia of an 

 instant's duration may be produced, which is sufiicient for some 

 slight operations. 



Systemic Action, For genferal anesthesia, the drug is vapor- 



