The senses, their division and work : viewed physically and evolutionally / by Henry Muirhead.
- Muirhead, Henry.
- Date:
- [1877]
Licence: Public Domain Mark
Credit: The senses, their division and work : viewed physically and evolutionally / by Henry Muirhead. Source: Wellcome Collection.
Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.
16/18 page 333
![direct attention to feelings, to group spatial and chronal relationships of objects and processes. Moreover, although it shews what actinic rays seem to do, further investigations are yet required to find out the modes of operating of thermal and photal rays, which appear to be more immediately concerned in exciting to thermal and photal sensation.] Discussion on Dr. Muirhead’s Paper. Professor M'Kendrick, M.D., said he had listened with great interest and pleasure to the paper read by Dr. Muirhead. He had certainly taken a wide view of a subject which would lead into very intricate and difficult questions. He was particularly interested in the purely physical way in which Dr. Muirhead had tried to examine sensory impressions. This was the true way to get at a thorough understanding of nervous mechanism. Quite recently 1 there had been several attempts made to ascertain what really occurred in the terminal organs of sense under the action of parti- cular stimuli. Por instance, the question had often been suggested —what was the particular action of light upon the retina, and the action of sound upon the terminal organs in the intricate mechanism of the ear 1 Por a long time this subject baffled investigation, but now it was known that by careful arrangements, and with proper instruments capable of delicate measurements, a change in its i electrical condition could be made out in the optic nerve under the influence of light. Light produced a distinct and specific chemical change in the retina, which change might be manifested at once to the senses by an electric variation, which could be detected and measured by a galvanometer and other delicate apparatus. It had also been shewn that the action of light upon the retina was nearly similar, even in quantitative results, to the action of light upon a sensitive plate of chloride of silver, such as was used in certain photographic arrangements. Up to that time no one had succeeded in making out exactly what happened in the terminal appai-atus of the ear, but quite recently he had satisfied himself that odours produced a specific change in the olfactory nerves,—a change similar in character, so far as could be measured by the galvanometer, to that which occurred in the retina and optic nerve with the stimulus of light. By investigating such problems, physiologists might help such thinkers as Dr. Muirhead in still further effecting a complete correlation between physical forces and agencies outside of themselves, acting on the terminal organs of sense, and those processes which take place in our nervous mechanism. He had listened to the paper with great pleasure, and hoped to read it in the printed Proceedings. Such investigations](https://iiif.wellcomecollection.org/image/b24761916_0019.jp2/full/800%2C/0/default.jpg)
