On a new theory of nervous action as regards the transmission of sensation along the nerves / by Robert M'Donnell.

  • M'Donnell, Robert.
Date:
[1870]
Catalogue details

Licence: Public Domain Mark

Credit: On a new theory of nervous action as regards the transmission of sensation along the nerves / by Robert M'Donnell. Source: Wellcome Collection.

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    A NEW THEORY OF NERVOUS ACTION AS REGARDS THE TRANSMISSION OF SENSATION ALONG THE NERVES. BY ROBERT M‘DONNELL, M. D., F. R. S. [Abstract.] [Read before the Royal Irish Academy, May 23, 1870.] A large number of facts have of late years been observed, tending to show that what has hitherto been regarded as the sense of touch is ca¬ pable of being resolved into a number of comparatively elementary sen¬ sations, as those of temperature, contact, tickling, pain, &c. Many cases have likewise been observed in which some of these sensations are felt, while others cease to be perceived by the patient. Thus the individual may feel perfectly the contact of the hand, when lightly rubbed over the surface, yet not be able to distinguish heat from cold, or vice versa. Analogous phenomena are observed with regard to the other senses, as in cases of colour blindness, absence of ear, or inability to hear par¬ ticular notes, &c. In explanation of these and other kindred phenomena, it has been supposed that there exist in every nerve groups of distinct conductors, each adapted to convey along it distinct nervous impressions. This hypothesis is indeed that which is at the present time adopted by physiologists, and it numbers among its supporters the most distin¬ guished philosophers. Dr. Brown-Sequard conceives “that he has ascertained that, beside the four distinct kinds of nerve fibres of the higher senses, there are at least eleven kinds of nerve fibres in the spinal cord, and in the cranial, spinal, and sympathetic nerves.”