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Man's curiosity has led him to seek methods of investigating the inner workings of the human body, but it is only recently that it has become possible to properly visualise the inner cavities of the human frame. Physiologists such as William Beaumont have occasionally had the opportunity to see the function of the gastrointestinal tract, in this case the gastric fistula of Alexis St Martin who was injured following an accidental firearm explosion. Rigid instruments, down which lights are shone, can be used to visualise the respiratory passages, the gullet, the rectum, and the bladder, and in the past artists were employed to record what was seen. Such instruments are still in use, although light from a powerful source is now conducted down the instrument using a fibreoptic bundle. The first semi-flexible instrument which could be inserted into the stomach and used to visualise its walls was developed by Schindler and Wolf in Germany in 1932. The optics consisted of a series of convex-lenses, transmitting an image back to the eye, but again the view obtained was limited and since its optics were side viewing, the gullet could not be viewed. The advent of fibre-optics revolutionised the situation, and the first fibrescope conducting the image up a fibreoptic bundle was a side-viewing instrument, developed by Hirschowitz, Curtiss, Peters and Pollard by 1958, and used for viewing the stomach. Since those pioneering days, the development of fibrescopes for viewing every potential cavity in the human body has proceeded in leaps and bounds.
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