On the relation between muscular contractility and the nervous system / by John Reid.

  • Reid, John, 1809-1849.
Date:
[1841]
Catalogue details

Licence: Public Domain Mark

Credit: On the relation between muscular contractility and the nervous system / by John Reid. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    ter this a weaker battery was used, and the muscles of the limb* had- recovered their contractility, and contracted powerfully. The more powerful battery was used as before, until the muscles had ceased to respond to the excitement, and three days after this they had again recovered their contractility. Exper. 2.—The sciatic nerve was divided in a rabbit, and a portion of it removed. Seven weeks after the operation, the animal was killed by a dose of prussic acid, and the nmscles of both posterior extremities were exposed and irritated by the di- rect application of the wires of a galvanic battery to the muscles. The muscles of the leg of the paralysed limb contracted very feebly, while those of the other leg were thrown into powerful contraction. The muscles of the leg of the paralysed limb were evidently much smaller, paler, and softer than the corresponding muscles of the opposite leg. The muscles of the two legs were then carefully removed, and weighed in a delicate balance, and their respecti\'e weights were as follows :— Weight of the nmscles of the leg of the sound limb, . 327 grains. Weight ot the tibia and fibula of sound limb, . . 89 pai-alysed, . . .81 On examining portions of the muscles of both legs under the microscope, a very obvious difference in the physical appearance in the muscles of the two limbs at once presented itself. The muscular fibres of the paralysed leg were considerably smaller, had a somewhat shrivelled appearance, and the longitudinal and transverse strire were much less distinct than in the muscles of the sound leg. From these experiments, we believe we are justi- fied in concluding,—First, That in the warm, equally as in the cold- blooded animals, the contractility will return as vigorously as be- fore in muscles which have been insulated from the central organs of the nervous system, and their contractility exhausted, or at least much enfeebled. Secondly, That the loss of contractility which subsequently occurs in muscles insulated from the central organs of the nervous system, may be satisfactorily explained by their imperfect nutrition, consequent upon the state of inaction into which they are thrown. To decide whether or not this imperfect nutrition was depend- ant upon inaction, or upon any supposed nervous influence flow- ing along the nerves to the muscles, another series of experiments was performed. Exper. 3.—The spinal nerves were cut across, as they lie in the lower part of the spinal canal, in four frogs, and both poste- rior extremities were thus insulated from their nervous connec- tions with the spinal chord. The muscles of one of the paralysed limbs were daily exercised by a weak galvanic battery, while the muscles of the other limb were allowed to remain quiescent.