The senses and the intellect.

  • Bain, Alexander, 1818-1903.
Date:
1885
Catalogue details

Licence: Public Domain Mark

Credit: The senses and the intellect. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    the root of a nerve is attached to the surface, in order to dis- tinguish it from the ' real or deep origin/ which is beneath the surface and concealed from view. * To trace the different nerves back to their real origin, and to determine the points where, and the modes in which their fibres are connected with the nervous centre, is a matter of great difficulty and uncertainty: and, accordingly, the statements of anatomists respecting the origin of particular nerves are, in many cases, conflicting and unsatisfactory. Con- fining ourselves here to what applies to the nerves generally, it may be stated, that their roots, or part of their roots, can usually be followed for some way beneath the surface, in the form of white tracts or bands, distinguishable from the sur- rounding substance; and very generally these tracts of origin may be traced towards deposits of grey nervous matter situated in the neighbourhood, such, for instance, as the central grey matter of the spinal cord, the grey nuclei of the pneumogastric and glossopharyngeal nerves, the corpora geni- culata (attached to the corpora quadrigemina), and other large grey masses connected with the origin of the optic nerve. It would further seem probable, that certain fibres of the nerve roots take their origin in these local deposits of grey matter, whilst others become continuous with the white fibres of the spinal cord or encephalon, which are themselves connected with the larger and more general collections of grey matter situated in the interior or on the surface of the cerebro-spinal axis. As has been already more fully stated, there is a difference of opinion as to the mode in which the nerve fibres, supposed to arise in the grey matter, are con- nected with its elements; some anatomists describing them as forming loops or arches in the grey matter, passing into it, as it were, and returning, whilst others maintain that the fibres are prolonged from the caudate nerve cells/—Id. ccxiii-v. ' Termination or Peripheral Extremity of Nerves.—The results of modern microscopic discovery seemed for a time to lead to the conclusion that the fibres of nerves do not, strictly speaking, end in the tissues in which they were distributed, but merely dip into those tissues, as it were, and, after forming