Medical instrument - Metal - Vintage spirometer

Vintage spirometer, Germany about 1950
Also to be found in 'Triptych collection of equipment Dutch heritage, Physiotherapy collection breathing therapy and pandemics' by the Stichting Geschiedenis Fysiotherapie.
In addition to the inhalation equipment aimed at nebulization and inhalation therapy, the collection also includes measuring instruments used with patients with respiratory disorders (vital capacity meter, spirometer, etc.).
Here we see a fine example of a device that can measure vital capacity.
This identical device is also included in the collection.