Segalas's Speculum

Still dangerous in use

The groundbreaking feature of the speculum urethro-cystique, which Pierre Salomon Ségalas (1792-1875) presented in 1826 to the Parisian Academy of Sciences, was its construction concept. The instrument was designed primarily for inspecting the urethra and interior of the bladder.

The speculum urethro-cystique consisted of two silver tubes, two metal mirrors, two small candles and an elastic probe. The urethra tube which was polished on the inside, expanded into a conical mirror. In front of the mirror, two candle flames were held with the left hand. A concave, spherical mirror reflected the light in the conical mirror and therewith the urethra. A hardened rubber obturator served for insertion, and an ocular funnel, which had been blackened on the inside, protected the eye.

The speculum urethro-cystique was lighter than Bozzini’s Lichtleiter and it was easier to operate. However, one of the most troublesome drawbacks related to the uncovered candles, which presented some danger of burning. Other complaints on the record relate back to the limited number of clinical trials Segalas was actually able to conduct. For instance, during the time period from 1826-1828, he reported only three clinical cases. There is no record which suggests the reasons for such a limited number of clinical cases. In the worst case, it could suggest that perhaps a greater failure rate occurred than was officially reported.

Another discrepancy in the record has to do with the claim that Segalas’ device enabled him to visualise and therefore accurately diagnose a bladder stone in a three-year-old girl who subsequently underwent an operation for its removal. In any case, Segalas’ innovations were in fact mentioned in the prestigious British Journal, The Lancet. 

Source: Nezhat’s History of Endoscoy. Online.

Drawing of the speculum urethro-cystique by Pierre Salomon Ségalas. From the Int. Nitze-Leiter Research Society for Endoscopy.

Ségalas opted for a concentric arrangement of the light and image transport. His tube oculaire (image transport) lies in the centre of the endoscope shaft, surrounded and enclosed by the light-transport tube. By dispensing with a fixed light source, Ségalas endeavored to get around using the large “light receptacle”.

Ségalas’ speculum was therefore one of the few instruments in the infancy of endoscopy that had no “light receptacle” – that part of the instrument in which the light source was permanently fixed. This fact may have made the speculum on the one hand a little lighter, and probably easier to handle, on the other hand it required special skill on the examiner’s part. One hand was taken up solely with holding the two candles in the area between the two mirrors and directly beside the inner examination tube and the “reflector cone”, without knowing whether the light source was positioned just right and burning steadily and evenly.

In addition to its job of “trapping” or channeling as much light as possible, the cone at the proximal end (the one nearer the examiner) of the instrument’s shaft, had another function. It also acted as a mirror or “reflector cone” that was designed to reflect the candlelight in the mirror attached more towards proximal in the inner tube in order to improve “light transport” into the body cavity.

Source: Peter Paul Figdor: The Development of Endoscopy in the 19th century. Tuttlingen, 2004, pp 83-85.

This site uses cookies. Read more about our privacy policy.