ON ANAESTHETICS. 169 



of these lessons is that excitement and struggling during anaesthetisa- 

 tion are referable, in the majority of cases in which they arise, either 

 to (1) imperfections in the inhaling system or actual apparatus, causing 

 suffocative sensations, or (2) irregularities in the vapour concentration, 

 causing irritation to the mucous membrane of the upper air-passages. 

 In this connection I would again draw attention to the importance of 

 the ' plenum ' system of administration. Any method by which the 

 diluted anaesthetic gas or vapour is drawn through comparatively narrow 

 channels by the inspiration of the patient is to be deprecated, not only 

 on account of the constant stress thrown upon the respiration through- 

 out the administration, necessitating, in certain subjects, the use of 

 oxygen to correct the air limitation thus introduced, but on account 

 of the excitement and struggling which such a system of administration 

 is likely to initiate at the very outset, when a patient is conscious or 

 semi-conscious. As is well known, the impact upon the fauces, naso- 

 pharynx, and larynx of frequently varying strengths of anaesthetic 

 vapour is liable to produce numerous reflex phenomena, such as breath- 

 holding, swallowing, and coughing; but it is not generally recognised 

 that such irregular strengths are also often responsible for the struggling 

 and excitement of the induction stage. It would seem that irregular 

 concentrations of vapour have the same effect upon half-conscious 

 patients as cutaneous stimuli which, as is also well known, are par- 

 ticularly liable to induce struggling if brought to bear during the early 

 stages of anaesthetisation. It is found, in practice, that the more 

 closely the anaesthetist can imitate the physiologist by presenting to his 

 patient a dilute vapour of definite strength, or one which very gradually 

 increases in strength, the less will be the liability to the phenomena in 

 question. The second important lesson which we have learnt is that 

 gradual methods of induction, although possessing certain slight disad- 

 vantages as compared with rapid methods, have the great advantage of 

 securing during the operation a degree of muscular relaxation and 

 general quietude which are rarely to be obtained when rapid and com- 

 plicated methods of induction have been employed. Ever since the 

 days of Clover the practical anaesthetists of this country have been vying 

 with one another in their endeavours to eliminate the excitement and 

 struggling stages of anaesthesia by the use of various anaesthetic com- 

 binations and sequences, and it may be said that they have been suc- 

 cessful in their object. Eapidity of induction has been regarded as 

 more or less synonymous with skill. By means of such anaesthetics 

 as nitrous oxide and ethyl chloride, and by the use of specially con- 

 structed inhalers, it has been found possible to plunge patients into 

 deep anaesthesia in from one to three minutes, and from some points of 

 view such methods doubtless have much to recommend them. But, 

 thanks to the combination of physiological experiment and clinical 

 observation, we are now able to formulate the proposition that the use 

 of these rapid induction methods is liable to be followed by difficulties 

 and complications which do not present themselves when slow methods 

 of induction have been employed. Fortunately the modern surgeon is, 

 or should be, in no sort of hurry; and it is an easy matter for the anaes- 

 thetist to commence the anaesthetisation ten or twelve minutes before the 

 surgeon is actually ready to begin the operation. It is true that in the 



