The experimental method in medical science : second course of the Cartwright Lectures of the Alumni Association, College of Physicians and Surgeons, New York delivered January 24, January 31, and February 7, 1882 / by John C. Dalton.

  • Dalton, John Call, 1825-1889.
Date:
1882
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Licence: Public Domain Mark

Credit: The experimental method in medical science : second course of the Cartwright Lectures of the Alumni Association, College of Physicians and Surgeons, New York delivered January 24, January 31, and February 7, 1882 / by John C. Dalton. Source: Wellcome Collection.

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    in which it appeared that mechanical irritation of the anterior roots caused convulsion in the corresponding muscles, while a similar irritation of the posterior roots had no such effect. This, however, was not supposed to show an anatomical separation between the two powers of motion and sensibility, but between those of volition and consciousness on the one hand, and involuntary nervous action on the other. The ideas of the author on this sub- ject were not accepted by his colleagues. In fact, they were not really published, but only printed in pamphlet form for private distribution. They hardly attracted the notice of the profession, and had no influence on the medical doctrines of the day. Subsequently, in 1821, Bell published1 the remarkable observation that if the seventh cranial nerve, distributed to the face, were divided in a living animal, the move- ments of facial expression were abolished; while the faculty of sensation could be destroyed by cutting the corresponding branches of the fifth pair. Thus the two main properties of nervous endowment, generally asso- ciated with each other, occupied in this instance distinct situations; since the seventh was shown to be a nerve of motion only, the sensibility of the face being supplied from another source. This fact was connected, in the re- searches of Sir Charles Bell, with theoretical considera- tions of a different bearing; but it had evidently a great importance of its own, and was received on all sides with much interest. It especially attracted the attention of Magendie, then at the height of his activity in physio- logical investigation. Magendie repeated Bell’s experi- ments on the seventh cranial nerve, and verified their results as to its exclusively motor properties. But he was 1 Philosophical Transactions of the Royal Society. London, 1821, p. 398.