THE ADMINISTRATION OF ANAESTHETICS 41 



of success are enormously increased if the agent can be 

 administered before respiration actually ceases. If this could 

 always be done, the proportion of deaths during ansesthetiza- 

 tion in the dog and cat would be infinitesimal. 



Smce chloroform is an agent which destroys life by 

 paralyzing either the respiratory or cardiac centres, and 

 sometimes both apparently at once, the objects sought for 

 m an antidote are those which will act as a stimulant and 

 restorative to either or both. It is important, then, that the 

 ana;sthetist shall select the one which seems most nearly to 

 fulfil these objects. 



In ammonia vapour, such as is evolved from liq. ammon. 

 fort., we have an agent whose therapeutic actions are those 

 of a general stimulant, both respiratory and cardiac ; but we 

 dare not give it in the form of a draught, because the patient 

 is unable to swallow, and we cannot inject it hypodermically, 

 on account of its slowness of absorption and irritant action, 

 whilst its intravenous injection is difficult, so that it is 

 usually given m the form of a vapour inhalation. It is 

 needless to remark that the respiratory apparatus must be 

 artificially induced to work if it has ceased to do so, in order 

 that the effect of the vapour may be shown on the body. 

 This is sometimes a source of difficulty, and when once the 

 respiratory organs have recommenced to work, the vapour 

 must not be too suddenly applied, or the reaction is apt to 

 be too severe. It must be used at intervals with discretion, 

 holding the bottle under the patient's nostrils for a few 

 moments and then withdrawing it. 



With amyl nitrite the chief action is that of a cardiac 

 stimulant, and it has the advantages of being non-irritant 

 and readily absorbed from mucous surfaces, so that it can be 

 administered on the tongue. The necessary dose, too, is very 

 small, and it can be given undiluted. For the dog or cat 

 about one-quarter of a minim for each pound of the body- 

 weight is a fair average dose. 



