284 Description of a Totally He fleeting Prism. 



them. Upon a first examination, the observer will be apt to 

 be satisfied with an indistinct view of objects which he has 

 been used to regard as beyond the reach of observation, and 

 the full power of prismatic illumination will therefore not at 

 once be appreciated. Those who have discovered objects 

 through the different tubes produced only in a shadowy and 

 shrouded light, can have but a very inadequate idea of the 

 much greater satisfaction attainable by the proper adjustment. 

 It will convey a notion of what is meant, when I mention that 

 through a tube of two feet in length and half an inch in bore, 

 I can discern, by a good light, slender initials impressed on 

 red sealing-wax, a test as sufiicient as any ever likely to be 

 required for recognising disease in the living body, be it in the 

 stomach itself. 



Although in this communication I have confined myself to 

 the consideration of prismatic illumination as applied to the 

 subjects pertaining to my own profession, it will readily occur 

 to the members of this Society, that it may be employed with 

 equal advantage in any department of the arts where light 

 could be used to test the interior condition and soundness of 

 straight narrow cylinders, such as valuable ordnance, &;c., and 

 also to some extent of tubes joined together at an angle. 



Adam Warden, M.D. 



3 Baxter's Place, Edinburgh, 

 12th April 1844. 



Report of Committee of the Royal Scottish Society of Arts on Dr War- 

 den's employment of the Totally Reflecting Prism for illuminating the 

 open Cavities of the Body, with a view to facilitate the examination 

 of disease, and the application of remedial means in such situations j 

 illustrated with an Ear " Speculum" adapted to this method of obser- 

 vation. 



Committee. — Dr Traill, Dr Douglas Maclagan, Dr Cowan, Dr Rans- 

 ford. Dr Ransford, Convener. 



The Committee met on Wednesday, 15th instant, and carefully ex- 

 amined this adaptation of the prism ; they found, that, in narrow pas- 

 sages, such as the auditory canal, the invention was peculiarly fitted to 

 assist in the discovery of disease ; and, from the reports of other medi- 

 cal men, that it was found to be equally satisfactory in examining other 

 cavities of the human body. 

 Dr Warden also laid before the Committee various surgical instru- 



