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.

    29/32 (page 25)
    me to be loss of one-lialf of the movement for the estimation of distance. Only one-half, for there is a one-sided lesion only. It will, I think, be seen that the speculation as to the repre- sentation of these ocular movements is verified by some of the results of Ferrier’s experiments on the cerebellum. And the further speculation that these ocular movements are represented by nervous arrangements in the cerebellum associated with movements of locomotion, goes also with Mr. Spencer’s hypo- thesis that the cerebellum is the organ for doubly compound co- ordination in space.” THE EYE AND EAR IN THE ESTIMATION OF SPACE AND TIME. In the Hospital Reports of the “ Medical Times and Gazette,” August 7, 1875, are some remarks by Dr. Hughlings Jackson, on the movements associated with hearing. In a former note (p. 325), it was pointed out that movements of the eyes are essential in the estimation of Extension (size and shape). In the following extract movements associated with the auditory nerve are spoken of as being essential in the estimation of Intervals. It is given here as it bears indirectly on the matter discussed in the note on the Anatomical Substrata of Visual Ideas. (See p. 335.) The auditory nerve is in two divisions; one, the cochlear, Dr. Hughlings Jackson thinks (having regard to Lockhart Clarke’s researches) is afferent to centres in the medulla oblon- gata for movements of the heart, and the' other (the tripartite division for the semi-circular canals) is afferent to centres for locomotion in the cerebellum. “ So far we have spoken separately of the two divisions of the auditory nerve as if one were an auditory and the other a sensory- locomotor nerve. We now consider their possible relations to one another. If it be, as above suggested, that the cochlear and the canal divisions of the auditory nerves are afferent respectively to the heart and to the movements of the head and neck (and thus indirectly to locomotor movements), we see that the com- pound nerve which is called ‘ auditory ’ has, saying nothing of the tensor tympani and stapedius muscles, much muscularity in dependence on it. Yet it differs notably from the eye, for the movements of the eyes are comparatively independent of those of the rest of the body—require translation into them,—while the movements which we are supposing to be associated with the ear are those constantly serving the organism as a whole. That is to say, the movements of the head and neck, are the first and most important of locomotor movements ; the heart is the most central of all organs. It is exceedingly important to note the double association of movement. For the fact of association of the ear and circulation bears on the anatomico-physiological process which goes on whilst we acquire ideas of Time. The ear is not merely for the estimation of sounds, but of Intervals ; d