Lastly, there remains the plan of using _ether as the main inducing agent_, but assisting its action by the intermittent and most guarded addition of small quantities of C_{2}E_{3} mixture. This is the author’s “stock” method; but in teaching it to students, too much emphasis cannot be laid upon the small quantities of chloroform mixture required or _permissible_. _As a consequence of the perhalational method here advocated, every drop of chloroform which appears on the mask will when volatilised, give a very much higher percentage of CHCL_{3} vapour in the inspired air, than the same quantity exhibited on the ordinary open chloroform mask._ Once the student has grasped this essential fact, ordinary care and intelligence will enable him to guard against a danger which is only existent if unappreciated. The Administration. For many of the hints given in this section the author is indebted to Dr W. J. Ferguson of New York, and Dr Hornabrook of Melbourne. Success in inducing with open-ether is attained only by attention to a number of small details. The student who thinks that some of these are too trifling for his notice is usually the man who informs you that induction by open-ether is impossible, the fact really being that he has not taken the trouble to learn, or has never had proper tuition. The following are the points demanding attention:-- 1. Always give a dose of morph-atropine or other narcotic, half to three-quarters of an hour beforehand. 2. See that the patient is comfortable on the table. Prop up his head and shoulders a little with pillows. In powerful subjects Hornabrook tilts the whole table down at the foot-end, for a few degrees. 3. Adhere strictly to perhalation and to the drop method. You will never induce with open-ether if the whole volume of the respired air does not pass through the gauze. 4. Chat to the patient as long as consciousness can possibly persist. Tell him he is doing very well. Don’t shout complicated instructions at him as to how to breathe: it annoys and muddles him. 5. When the gauze ring and the mask are in position, allow one or two drops of ether to fall on the mask, then pause: in a few seconds the mild ether vapour so formed will soothe the upper respiratory tract, and prepare it for the stronger vapours yet to come. This does not waste time--it saves it. 6. When the administration is again begun, attend closely to the rate of dropping. At first not more than one drop in three or four seconds is wanted. The full rate of dropping cannot be attained for at least ninety seconds. 7. Give no mixture for the first ninety seconds; thereafter some five to ten drops every half minute or every twenty seconds according to type of patient. Have the mixture bottle handy so that no time is wasted in changing bottles. Stop the addition of mixture as soon as full anæsthesia is attained.