Note 13 — CHAP. IV. Of the Natural Cure.

To say that Voluntary Motions by custom become Involuntary, may appear a contradiction; but if we reflect on several phænomena of Animal Motion, that assertion will not appear so absurd. ’Tis universally allow’d, that the Muscles of the Larynx and Tongue, Adductors and Abductors of the Eyes are of the Voluntary kind; yet, by endeavouring to imitate those who Stammer or Squint, these disagreeable habits are acquir’d so, as not to be afterwards corrected by the strongest efforts of the Mind. As the Heart of an Infant beats, at a mean, about 11520 times every 24 hours, during the first year, ’tis probable, that, by this frequent Motion, the action of that Muscle may become independent of the Will ever afterwards: tho’ it might be as Voluntary at first, as the action of the Muscles concern’d in sucking the Nurse’s Breast.