NO INSTRUMENT in general medicine has influenced and developed a specialty as the ophthalmoscope has done for ophthalmology. In addition, the ophthalmoscope has been of importance in other branches of medicine, as it stimulated the development of instruments for examination of other parts of the body, such as laryngoscopy, rhinoscopy, gastroenteroscopy and cystoscopy. In this connection, it should be stated that the exact date of the discovery of these methods cannot be given. A report of the conditions which led to the discovery of the ophthalmoscope may be of interest to those less informed, and its publication is timely in view of the centenary of the day when von Helmholtz presented his discovery before the Physical Society in Berlin, on Dec. 16, 1850. There is no question in my mind that the sturdy ophthalmoscope will survive its one-hundredth birthday, a prospect which is not necessarily applicable to my own case,