A physician's notes on ophthalmology. 2nd series / by J. Hughlings Jackson.

  • Jackson, John Hughlings, 1834-1911.
Date:
[1875]
Catalogue details

Licence: Public Domain Mark

Credit: A physician's notes on ophthalmology. 2nd series / by J. Hughlings Jackson. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

    25/32 (page 21)
    The following, from the “Medical Times and Gazette,” May 29, 1875, refers to the same subject. As the opening sentences show, it is from a paper dealing generally with the representa- tives of movements in the cerebral convolutions :— “ To myself, who have for more than ten years been teaching that convolutions represent movements, it naturally comes easy to believe that the experiments of Hitzig and Ferrier are a demonstration that this is the anatomical constitution of certain of them. Those who have read the quotations above given, will not accuse me of affectation when I say that I was surprised that any one hesitated to accept the conclusions of the recent experi- ments. My own opinion is that the prevalent confusion of psychology with the anatomy and physiology of the nervous system is much to blame for the incredulity. ‘ Centres for ideas ’ are often spoken of, but nothing at all is said of the anatomical substrata of any class of ideas. I hold that the anatomical sub- strata of ideas are sensori-motor arrangements. It seems to me to be plain, almost to demonstration, that there must be a motor element in the substratum of a visual idea. How else could we possibly have ideas of the shape and size of an object ? I beg the reader to take note that this is not an after-thought. I do not write this because Hitzig and Ferrier find that they develope movements of the eyes by electrical excitation of certain parts of the cerebral cortex. I believed that movements of the eyes must be represented in the cerebral hemispheres before their experi- ments were begun. Before it was surmised that movements could be produced by artificial excitation of the brains of healthy animals, I wrote as follows (‘Medical Times and Gazette,’ October 23, 1869) of the anatomical substrata of visual ideas:— ‘ In the organised forms which serve as the mental representa- tives of objects when the objects are absent, there will therefore be comprised not only impressions of surface, hut residua of movements. . . . The speculation supposes that we have particular visual impressions in fixed association with particular ocular movements. A convulsion in which the eyes are strongly deviated is owing to an excessive discharge of a part where the motor elements of the substrata of visual ideas are largely represented.” ON THE MOST GENERAL MODE OF REPRESENTATION OF THE MOTOR AND SENSORY ELEMENTS OF VISUAL, ETC., IDEAS. In the same series of paper, Dr. Hughlings Jackson puts forward a speculation as to the most general mode of representation of the motor and sensory elements which enter into the substrata of ideas—visual ideas being the illustration. He thinks (quoting from an abstract of one of his Gulstonian Lectures, “ Brit. Med. Journal,” March 6, 1869), that “ facts seem to show that the fore part of the hrain serves in the motor aspect of mind, and we may fairly speculate that the posterior serves in the sensory.”