Fig. 395.

Pereira Fig 395

a. Outer case, containing water-bath, screwed on--b. Cylindrical vessel, into which the chloroform is put; it is lined with a coil or two of bibulous paper up to the point c. d. A cylindrical frame which screws into b; it has apertures at the top for the admission of air, and its lower two-thirds are covered with a coil or two of bibulous paper, which touches the bottom of the vessel b, except where the notches, e, are cut into it. f. Elastic tube. g. Expiratory valve of face piece--the dotted lines indicate the position of this valve when turned aside for the admission of air not charged with vapour. h. Inside view of face-piece, pinched together at the top to adapt it to a smaller face. i. Inspiratory valve.
Directions for use.--Unscrew the outer cylinder, and put into it as much water as will fill it when replaced; about 60' F. is the most suitable temperature for the water. Having replaced the water-bath, the chloroform (one to three fluidrachms, according to circumstances) is to be put into the inhaler, and the face-piece is next to be attached to it by means of the elastic tube. The face-piece should be moulded to the features of the patient, with the expiratory valve turned to one side, in the direction of the dotted lines in the engraving, and then this valve should be moved a little at each inspiration, till it gradually covers the opening; by this means the air charged with vapour from the apparatus will be admitted by degrees, to the exclusion of external air, and thus any irritation of the air-passages, which might arise from the sudden access of air charged with vapour, will be avoided. It is recommended by Dr. Snow that the expiratory valve should be partially moved aside if the patient's breathing be deeper or more rapid than in the natural state, and generally, also, in repeating the inhalation, to keep up insensibility during and operation. The lid which screws over the apparatus preserves any chloroform that is left until another occasion.

This image is from _ in Pereira's Elements of Materia Medica and Therapeutics, 1854.