76 ANAESTHETICS 



The A. C. E. Mixture consists of one part of absolute 

 alcohol, two of chloroform, and three of pure ether. It is 

 much used on the continent of Europe, and is stated to be 

 more stimulant than chloroform, and less likely to depress 

 heart action. A mixture of equal parts of ether and chloro- 

 form is used in various parts of France and Germany. The 

 Austrian Government has advised one part of chloroform 

 with six of ether in winter, and with eight of ether in summer. 

 The theoretical arguments in favour of these mixtures have 

 not been justified in practice. Alcohol, chloroform, and 

 ether volatilise at different rates and at different tempera- 

 tures, so that the composition of the vapour inhaled does 

 not remain constant ; at first the animal receives chiefly 

 ether, and this necessitates a high concentration of vapour 

 to air. Later, the chloroform becomes the chief constituent 

 of the vapour, and the former concentration becomes highly 

 dangerous. Since there is nothing to indicate this variation 

 in composition, the mixture increases, instead of lessening, 

 the risk. Chloral hydrate is given by the mouth or rectum, 

 or by intravenous, or intraperitoneal injection. It depresses 

 the heart and vaso-motor centres, and consequently the 

 vessels dilate and blood pressure falls. METHYLENE 

 (CH 2 C1 2 ), containing an atom more of nitrogen and an atom 

 less of chlorine than chloroform, causes more rapid anaes- 

 thesia, but requires to be used in larger amount. The pure 

 drug has also the disadvantage of being costly, and that 

 usually sold is stated to be a mixture of chloroform 

 and alcohol. METHYLAL, which has also been used, acts 

 quickly and effectually on dogs without apparent in- 

 jurious after-effects, and is also serviceable for local 

 anaesthesia. 



Anaesthesia is generally divided into four stages I. Sti- 

 mulant ; II. Narcotic ; III. Anaesthetic ; IV. Paralytic. 



I. The stimulant stage is characterised by symptoms of 

 inebriation, more marked in the case of ether than of chloro- 

 form ; excitation of cerebral and cardiac functions ; vigorous 

 animals struggle ; the pulse is accelerated usually from 

 nervousness or fear, and respiration is irregular and quick- 

 ened ; the pupil is dilated ; the special senses and general 

 sensibility are blunted. This stage usually continues from 



