It is a remarkable phenomenon, that every kind of affection in any degree strong, arising in the economy, alters immediately the motions of the heart. The least wound, oftentimes the slightest pain are sufficient to produce derangements in it; now these derangements are of two kinds; sometimes its action is arrested for a moment; hence syncopes, a mode of derangement which happens especially in violent and sudden pains. The vulgar expression which is employed in these cases, viz. "my heart is failing," is perfectly true. Sometimes, and this is the most common case, this action is accelerated; hence the febrile motions so frequent in all the local affections, motions purely sympathetic and which cease when the affection disappears. In many local inflammations, the evil is too circumscribed to admit an obstacle to the course of the blood, an obstacle, which according to Boerhaave, forces the heart to redouble its action to surmount it; besides when there is no swelling, but only pain in the part, and the febrile motion comes on, it is there clearly a sympathetic phenomenon. The increase of the action of the heart may depend no doubt upon a foreign substance, which, mixed with the blood, alters and renders it more irritating; it may be owing to an affection of the substance of the organ which disposes it to be more irritable; but it is certainly very often sympathetic, and depends upon that unknown relation which connects all our organs, upon that consensus which links together all their actions, and places them in reciprocal dependance.