Licence: Public Domain Mark
Credit: Syllabus of lectures on physiology / by Allen Thomson. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
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![U) § 57. Connection of the Cerebro-Spinal and Ganglionic Nervous Systems with Sensation and Motion. ]. Of the Spinal Cord and Mednlla Oblongata as conductors of sensory impressions and of motory influence. a. The spinal marrow ; structure of its columns, and relation to these of the roots of the nerves proceeding from the spinal chord. Does the spinal marrow consist merely of the united fibres of the spinal nerves, or are these combined in it with fibres of another kind ? Do the fibres of the roots of the spinal nerves or of the spinal marrow itself continue separate from one another in the whole length of the spinal marrow ? Re- searches of Gall, Bell, Rolando, and Bellingeri. Relation of experiments, shewing that volition and other stimuli are con- ducted downwards towards the roots of motory nerves, principally, if not solely, by the anterior columns of the spinal cord, while the impressions of sensation are transmitted from the roots of the sensory nerves upwards to the brain, principally, if not solely, by the posterior columns. First experi- ment of Magendie in proof of this ; confirmatory experiments of Beclard, Flourens, Amussat; late and accurate experiments of Backer, J. Muller, and Seubert. The results of these experiments not as yet satisfactory. Experiments of J. Miiller, shewing that a mechanical or galvanic stimulus may be conducted either upwards or downwards by the spinal cord, so that irritation of either the upper or lower part may produce contractions of the muscles, deriving their nerves from the opposite extremities of the cord re- spectively. Experiments seeming to prove that both columns to a certain degree con- duct impressions of sensation and motory influence; of Schoeps, Fodera, Ro- lando, and Bellingeri; opinion of Bellingeri that contractions of the extensor muscles are excited through the posterior, those of the flexor muscles through the anterior columns of the spinal cord, and that while the spincters are re- laxed through the posterior they are contracted through the anterior columns; objections to these views. Speculations respecting the difference in the properties of the white and grey matter, and of the central and superficial part of the spinal cord. Opinion of Bellingeri that sensation belongs to the grey substance, motion to the white substance of the spinal marrow ; observations opposing this view. b. The medulla oblongata. Observations ofBurdach, Rolando, Bell, Rosen- thal, and others, on its structure. The experiments on the functions of this part not so conclusive as those on the spinal cord. The medulla oblongata less purely a conductor and more distinctly a source of nervous influence than the spinal marrow. Ex- periments, taken along with the analogy of structure and the similar origin of nerves from both, seem to prove that the conducting function of the an- terior and posterior parts of the medulla oblongata, corresponds very much with that of the similar columns of the spinal cord ; in some experiments, however, pain and muscular contractions have proceeded from the irritation of either of the columns of the medulla oblongata ; experiments of Flourens and Hertwig. How does the decussation of the pyramidal columns affect this ? In most of the experiments the injury of one lateral half of the me- dulla oblongata has occasioned palsy on the same side.](https://iiif.wellcomecollection.org/image/b21979571_0052.jp2/full/800%2C/0/default.jpg)
