A letter to the Right Reverend Samuel, Lord Bishop of St. David's : occasioned by his sermon on the principle of vitality in man, &c. preached on Sunday, March 22, 1789, for the benefit of the Humane Society.

Date:: 1789

Credit: A letter to the Right Reverend Samuel, Lord Bishop of St. David's : occasioned by his sermon on the principle of vitality in man, &c. preached on Sunday, March 22, 1789, for the benefit of the Humane Society. Source: Wellcome Collection.

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$[ 3° ] than others, each difclaims any even the moft remote alliance with your Lordfhip’s clock- mechanifm * 44 In any fyftem of bodies, or particles of matter, affeding 44 one another only by the motions already exifting in them be- ** ing communicated to one another, they may diminilh their motion, or bring one another to reft ; but they never can in- 44 creafe the motion exifting in the whole. It happens fre- 44 quently, that the motions in the animal body are increafed, 44 without any alteration of external applications to it: the 44 cafes are fo numerous, that it is hardly worth bringing an ex~ ample; we might mention the increafe at times, of the circu- “ lation, and all the motions of the fluids, without the leaft new 44 motion in the furrounding bodies, or interference, or even knowledge of the mind. This motion mu ft therefore be ori« at ginal, and not communicated. 44 In communicated motion, if one body be at reft, and a *‘ motion be communicated to it by another, the power of the 44 whole motion fhall not be greater than that in the communk “ eating body at the time of the communication. If I take out 44 the heart of an animal, cut off the auricles, it will in many 44 cafes continue to contract and dilate for fome time. If it be ** left to come to reft, and if foon after a needle be introduced “ into the ventricle, placed tranfverfely, and if the interior fur- face of the ventricle be pricked gently by the needle, the ven- et tricle will contrad with fuch power as to force the needle deep 44 into it: in this cafe, the force of the contradion of the ven- 6< tricle is much greater than the power with, which it was 44 pricked by the needle; this contradion was therefore not 44 communicated to it by the moving needle, but was generated, 94 and therefore an original motion.5’ Dr. G. Fordyce, Phil, ''TravJ,\ vol. lxxviii, p. 24.—I fuppofe it will be allowed, that the motion of clock-work is communicated motion. But$