Dit. Buchanan on the Effects of the Inhalation of Ether. 1 85 



of ether absorbed will, in tin: same circumstances, be always nearly in the 

 same proportion to the quantity inhaled, we are enabled to measure, or 

 at least adjust, the done of ether by the sure and simple standard of the 

 time during which the inhalation is continued. The only other criterion 

 of the quantity of ether administered is the physiological effects resulting 

 from it, such as the appearance of the eye and the state of the sensibility; 

 but these, although worthy of being noted, are too vague and difficult of 

 ition to be relied upon alone. 



It follows from what has been just said, that the form of the inhaling 

 apparatus is of the utmost importance, and should not be regarded as a 

 matter of mere taste and convenience, as if there were no more stable 

 principles to regulate it. Much risk is incurred by the diversity of 

 instruments at present in use. It is, moreover, clear that no comparable 

 results eat) 1"' expected so long as an indiscriminate use is made of instru- 

 ments differing BO much, that one produces full narcotism in from five to 

 ten minutes, and another can be employed from two to four hours with 

 impunity. Admitting fully the influence of idiosyncracy, we cannot, 

 without abandoning all faith in the uniformity of the laws of living nature, 

 explain such discrepancies on that principle, and a little consideration 

 will show that an obvious explanation of them is to be found in the mere 

 difference of size and structure of the instruments made use of. 



In constructing an inhaling apparatus, and in making use of it, every 

 other consideration should be made to give way to the vitally important 

 object of administering a definite quantity of ether in a given time, and 

 haying it mingled with such an unvarying proportion of atmospheric air 

 as may be sufficient to support respiration. Now, to attain that object, 

 the apparatus should always be employed at the same temperature; the 

 chamber m which the vapour is contained should be of large size; the 

 a pei -hires into it, and the tubes connected with it, should be at every point 

 somewhat larger than the human wind-pipe, and kept carefully free from 

 all obstructions ; and, lastly, there ought to be valves, or some similar con- 

 trivance, to direct the course of the gaseous fluid to and from the lungs. 



The temperature of 00° Fahr. is the most convenient that could be 

 selected. At that temperature, if the size of the chamber be large 

 enough to admit of the vapour retaining its maximum tension while the 

 inhalation is going on, the gaseous fluid consists nearly of equal volumes 

 of air and ethereal vapour; and experience seems to have shown that air 

 of that degree of tenuity, or of one half its ordinary density, may be 

 respired for a short period without any bad effects — although this cannot 

 be considered as fully ascertained, since probably even the largest inhalers 

 now in use are too small to fulfil the Conditions above-stated. If the 

 temperature bo higher than 60° we must cither lower it artificially 

 to the proper standard, or we must admit air into the ehamber so freely 

 as to prevent the vapour from attaining its maximum tension, which it 

 could not do without expelling so much sir from the chamh adet 



