The two inhalers originally brought out for this were Clover’s in London, and Ormsby’s in Dublin. At a later date Hewitt’s “wide bore” modification of the Clover was introduced. (_a_) _The Clover instrument_ (see Fig. 23)[4] consists of a face-piece, a dome-shaped ether chamber, and a one-gallon bag, usually attached to the top of the ether chamber by a =T=-shaped tube. The details of the method by which the amount of ether inhaled by the patient is graduated are best appreciated by unscrewing the milled head at the top of the dome, and withdrawing the tube which runs through it (_see_ Fig. 24). In the tube will be found two slots, one about half an inch above the other, and each extending for half the circumference of the tube. Between these two slots the tube is divided by a diaphragm. In any case, therefore, air passing up or down the tube must pass in and out of these slots. Now turn to the tubular space left in the dome piece, and examine visually and with the finger its interior. On the one side of its middle will be found two slots leading into the circular ether chamber which occupies a large part of the dome. On the other side will be found a small cavity, as deep from above downwards as the two slots combined, but _not_ communicating with the ether chamber. It is obvious that with the tube inside, if this cavity is opposite the slots in the tube, air will pass up the tube out of one slot and back into the other, without coming into contact with the ether at all. If on the other hand the slots in the tube are opposite the slots in the ether chamber, the air passes over the surface of the contained ether, and volatises some of it. Intermediate positions of the tube give a condition where part only of the air passes over the ether. The indicator attached to the tube, combined with the figuring “O, one, two, three, full,” to be found on the outside of the base of the dome, shows at any moment what proportion of the air is passing into the ether chamber. To use the instrument, fill the metal measure provided with ether, withdraw the stopper from the ether chamber, and pour in the ounce and a half of ether which the measure contains. Replace the stopper, and blow through the tube to expel any ether vapour which may have appeared in it. Leave the rubber bag at first unattached: the patient will feel more comfortable if during the first minute the top of the tube is open. With the indicator at 0 adapt the face-piece to the face and allow the patient to breathe up and down the tube. By rotating the dome, ether is then gradually turned on, until the figure two is reached in the first minute. The indicator is then slipped back nearly to zero for a second, and the rubber bag slipped on during an _expiration_: it must be moderately inflated to supply the requisite volume of air for respiration. [Illustration: FIG. 25.--Hewitt’s wide-bore ether inhaler.]