The Croonian Lecture

Abstract

Since the remarks, which the author has connected together on the present occasion, as tending, each of them, to promote the design of Dr. Croone, do not appear to bear any direct relation to each other, he divides the lecture into three distinct heads; the first of which contains an observation, and some experiments on the duration of muscular action. In the second he traces the origin of sea-sickness, from a mechanical cause deranging the circulation of the blood. In the third he offers a mechanical explanation of the advantages derived from riding, and the various modes of carriage exercise. With regard to the duration of muscular action, the author is of opinion that each effort, apparently single, consists in reality of a great number of contractions, repeated at extremely short intervals. He infers the existence of these alternate motions, from a sound observed upon inserting the extremity of the finger into the ear. The sound resembles that of carriages at some distance passing rapidly over a pavement. The sound is not perceived when the force applied to stop the ear is not muscular, unless the action of some distant muscle be communicated through some medium capable of conveying its vibrations.