274 



REPORTS ON THE STATE OF SCIENCE. 



anaesthesia. Skilfully employed, as is the practice at the Massachusetts 

 General Hospital, perfect anaesthesia is regularly secured, but by an 

 application of the mask so close and confined that the phrase ' open 

 ether ' is no longer properly applicable. 



Skilfully employed, as might be the case if the use of the ether- 

 balance were extended from the laboratory to the hospital, it would, I 

 venture to think, be very quickly discovered in the hospital, as it has 

 been in the laboratory, from comparative observations of the use of 

 ether and of chloroform under similar and known conditions, that 

 chloroform under such conditions is as safe as ether and more easily 

 managed. 



Therefore, although I am convinced that the ' ether-balance ' could 

 be employed in the hospital as effectively as it can be employed in the 

 laboratory, I do not recommend it as a hospital apparatus. Any 

 anaesthetist acquainted with the quantitative principles and use of an 

 ether-balance would necessarily be acquainted with the quantitative 

 principles and use of a chloroform-balance. No one, I imagine, familiar 

 with both instruments could fail to prefer the latter. And my principal 

 reason for describing the ether-balance has been that the description 

 involves considerations that are equally applicable to the chloroform- 

 balance, which, in my opinion, is equally safe and more serviceable. 



No instrument for the accurate administration of anaesthetics will 

 ever be devised that can dispense with the exercise of skill and judg- 

 ment. It requires some little skill to use a balance properly. Judg- 

 ment and experience are in any case, whether measuring instruments 

 be used or not, the necessary guide as to how much, and at what rate 

 and at what strength, an anaesthetic vapour must be exhibited to 

 different persons under different conditions. By reason of then- 

 physical and physiological qualities it has come about that chloroform 



the bulb doubles the value of the indications of any given scale, and halving again 

 doubles again. Thus 



with a bulb=800 c.c. the chloroform scale is 1, 2, 3 per cent. 



„ „ the ether scale is 2, 4, 6 



with a bulb =400 c.c. the chloroform scale is 2, 4, 6 



„ „ the ether scale is 4, 8, 12 



with a bulb =200 c.c. the chloroform scale is 4, 8, 12 



the ether scale is 



8, 16, 24 



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