Technical advances in various branches of science are eagerly and readily adapted, in many instances, to medical usage. Parts and activities of the living human body that were hitherto inaccessible may now be studied in vivo, thanks to developments in the field of medical electronics. Perhaps less glamorous, but not less useful, the science of optics has, by the development of fiber-optic lighting and optical-viewing systems, permitted visual exploration of other inaccessible regions.
Studies are presently being carried out to inspect by endoscope the interior of major blood vessels, as reported in the November issue of the Archives of Surgery.1 The instrumentation consists of fiber-optic optical and lighting systems housed in a plastic sheathe with an irrigation channel. Adjustable eyepiece and objective lenses allow proper focus and sharp images. At present the problem of visualization in a blood-filled vessel has not been solved, and all arterioscopic viewing must be