The Wood Library of Anesthesia describes this instrument as follows:

Stratford-Cookson Inhaler

” The pharmaceutical company Stratford-Cookson introduced this inhaler in 1907.  It was intended to be used with either of the company’s branded products, Somnoform or ethyl chloride. 

The oval cup at the bottom of the inhaler is enclosed by fine wire mesh.  For each procedure, this cup was packed with gauze.  The bottom of the cup was then inserted into a rubber re-breathing bag.  A glass ampoule of liquid anesthetic was placed in the capsule chamber (the tube that rises from the cup at an angle).  Then the tip of the ampoule was broken open by quickly sliding the “guillotine” lever on the side of the cup, and the released liquid was absorbed by the gauze. Any broken glass from the ampoule was also caught in the gauze.

As the patient re-breathed his or her own exhaled air through the bag and mask, carbon dioxide was continually added to the anesthetic vapor. Fresh air could be added by adjusting the lever beside the mask.  Compare this to the DeFord Inhaler, introduced five years later. “