Volume 1

Observations on man, his frame, his duty, and his expectations. In two parts / By David Hartley.

  • Hartley, David, 1705-1757.
Date:
1749
Catalogue details

Licence: Public Domain Mark

Credit: Observations on man, his frame, his duty, and his expectations. In two parts / By David Hartley. Source: Wellcome Collection.

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125/552 (page 93)
come equal, or nearly fo, in every Part of it, and are, at laft, fo exalted, as to contrad every Part. As foon as this Contradion takes place, the Vibrations in its fmall Particles mu ft ceafe, for Reafons given above. They will therefore be propagated almoft inftanta- neoufly over the neighbouring Mufcles, from the nerv¬ ous Communications between the Membrane and the neighbouring Mufcles *, by which all Changes made in the Nerves of the Membrane muft affed thofe of the neighbouring Mufcles. As therefore, during the vi- vid Vibrations of the Particles oi the Membrane, we muft llippofe fome to be propagated into the neigh¬ bouring Mufcles, agreeably to the Firft Article of this Propofition, fo, upon their fudden Celfation, fuch a Change may reafonably be fuppofed, in the communi¬ cating nervous Fibrils, as (hall agitate the iEther con¬ tained in them with much more vivid Vibrations than before ; and thefe Vibrations muft now pafs into the Mufcles alone, fince the Contradion of the Membrane hinders them from returning into it. I fnall here¬ after produce feveral Examples of this Procefs, in De¬ tail. It may fuffice, at prefent, juft to mention the Adion of Sneezing, and to defire the Reader to com¬ pare this Adion, in a curfory Way, with the fore¬ going Account. Fifthly, I have, in the laft Article, (hewn how a Ceflation of Vibrations, in the Particles of a Mem¬ brane, may increafe thofe in the neighbouring Mufcles. But it feems alfo, that a Ceftation of V ibrations in any other confiderable Part of the Body, from what¬ ever Caufe it proceeds, has a like Tendency •, and that this Tendency is deducible from the Change made in the Nerves of the Part affeded, and thence propa¬ gated into the communicating Branches, or even into the whole medullary Subftance. The Yawnings and Stretchings of Perlons difpofed to deep, the convul- five Refpiration of thofe that are juft fallen afleep, and the convulfive Morions which attend the Extin- * . dion