Observations on the structure and functions of the spinal cord / by R.D. Grainger.

Date:
1837
Catalogue details

Licence: Public Domain Mark

Credit: Observations on the structure and functions of the spinal cord / by R.D. Grainger. 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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    already been said as to the views of Dr. Hall and Pro- fessor Muller, it is only necessary to remark in this place, that neither of these writers have carried the great prin- ciple they have discovered, to what appears to be its full and legitimate extent. Dr. Hall states, that “ physiolo- gists have hitherto enumerated only three sources or prin- : ciples of muscular action, volition, the motive influence of respiration, and irritability. There is, however, a fourth source of muscular motion, distinct from any of these, though not hitherto distinguished, to which I have ven- tured to give the designation of the reflex function of the spinal marrow.”* Dr. Hall thinks that the heart and other muscles contract upon the principle of excited irritability, and, consequently, that their contraction does not depend upon the reflex function. Professor Muller, who in so many other respects limits the extent of the excito- motory phenomena, agrees in the opinion that the heart contracts in consequence of a stimulus acting directly on its substance; and he further remarks, that “ it is necessary to distinguish between reflected motions and the involuntary non-reflected motions.”f The inquiries in which I have been for some time engaged, induced me to believe that muscular contrac- tion J is only excited by three causes :—the first con- i listing of volition, the second of the reflex power pos- sessed by the spinal cord and the ganglions of the great sympathetic; and the third by the passions, fear, joy, &c. Contraction thus excited, is, I believe, the * Memoirs, p. 30. + Hand, der Phy. p. 698. + It is proper to state, that under this term I include the contraction ex- B-xerciscd by every organ, whether a muscle of the extremities, the heart, Ipie muscular coat of the intestines, the fibrous tunics of the blood-vessels, j ^of the secreting canals in glands, which produces perceptible motion ; in j act, every kind of contraction which is not attributable to elasticity. L