Three eustachian catheters, vulcanite and metal, in cardboard tube, Kramer's, 1900 to 1920
The three Eustachian catheters are seen with an otoscope and an explanatory picture showing it in use. They were used for the catheterisation of the Eustachian tube. This tube connects the nose with the middle ear. Catheterisation was commonly practised for therapeutic reasons or, when combined with an otoscope, diagnostic purposes.