Chapter 5 Images:
Figure 5.2. Snow's first inhaler, demonstrated at the WMS on 23 January 1847. "It consisted of a round tin box, two inches deep, and four or five inches in diameter, with a tube of flexible white metal, half an inch in diameter, and about a foot and a half long, coiled round and soldered to it. There was an opening in the top of the vessel, at its centre, for putting in the ether, and afterwards attaching the flexible tube belonging to the mouth-piece. In the interior was a spiral plate of tin, soldered to the top, and reaching almost to touch the bottom" (Lancet 1 : 120-21).
Figure 5.3. Snow's first modification of his inhaler. Snow first administered ether to surgical patients on 28 January 1847. Because "the sudden access of air highly charged with ether produces irritation and cough in some persons, I was desirous of having the means of diluting the vapour to any extent, and Mr. Ferguson, of Giltspur Street, who has taken great pains to carry my wishes into effect, got a tap cast of wide calibre, opening two ways, by means of which the patient can begin by breathing unmedicated air, and have this gradually turned off as the etherized air is admitted in its place. This tap offers the further advantage of enableing the medical attendant to keep up the state of insensibility during an operation by a more diluted vapour than that which was necessary to produce that state" (LMG 39 [19 March 1847]: 500-01).
Figure 5.4. Snow's ether inhaler, used exclusively from June 1847. His description: "A. Box of japanned tin or plated cooper, of the size and form of a thick octavo volume, serving as a water-bath when the apparatus is in use, and at other times containing the elastic tube and face-pieces. Attached to this by clasps, and moveable at pleasure, is B. The spiral ether chamber, of thin tinned brass, or copper plated with silver. C. Opening in ditto for putting in an pouring out ether, and for screwing on, D. Brass tube, by which the air enters which the patient inhales. E. Another opening in ether chamber for screwing on F. Elastic tube about three feet in length. G. Face-piece. H. Inspiratory valve of ditto. I. The same face-piece compressed, to fit it to a smaller face. S. Section of spiral ether chamber, B" (Snow, Inhalation of Vapour of Ether in Surgical Operations  ).