Mackenzie-Davidson telephone bullet detector

Mackenzie-Davidson telephone bullet detector, in leather case, owned by radiologist Russell John Reynolds (1880-1964), London, England, 1912-1916

Telephone probes were used in surgery to locate bullets and other metallic foreign bodies for extraction from the late 1800s. Invented by Alexander Graham Bell prior to the discovery of X-ray imaging, the device was refined by Scottish radiologist Sir James MacKenzie Davidson to verify the results of early X-ray localisations, enabling surgeons treating Boer War (1899-1902) casualties to differentiate between metal and bone fragments.

The instrument consisted of a telephone receiver with one terminal attached to a carbon plate which would have been placed in contact with a patient’s moistened skin. The other terminal was then attached to a probe or surgical instrument. When the tool touched an embedded metal, it produced a distinctive clicking sound in the receiver, alerting the surgeon to its precise location.

This example belonged to Russell Reynolds, an internationally renowned radiologist and specialist in the field of cineradiography (moving image X-ray films). While still at school, he – with the assistance of his GP father and physicist Sir William Crookes – constructed a fully functioning X-ray machine just months after German scientist Wilhelm Röntgen first described the ‘new type of ray’ in late 1895.

Qualifying as a doctor in 1907, Reynolds spent two years in general practice with his father before becoming a full-time radiologist. During World War I, he served with the Royal Army Medical Corps in British military hospitals and, from 1917-1919, as electrical specialist to the Karachi Brigade in India.