Sympathy denotes an unison or agreement of affections and inclinations ; or a conformity of natural qualities, or temperaments; in consequence of which two persons are mutually attached to each other. It also signifies the participation in pain or pleasure experienced by another individual ; though it is likewise defined to be an imitative and involuntary faculty ; for instance, yawning, and laughing, which affect different person in a similar manner, and at the same time.

Dr. Jackson considers Sympathy, as relating to the operations of the mind ; to the activity of the imagination; and to the impressions made on the external senses. Thus, he observes that the various passions and affections of the mind produce different corresponding sensations in the body, and generally determine the animal spirits to those parts which arc most liable to be influenced ; for instance, fear and anger to the heart; compassion, amazement or wonder, sorrow, joy, etc. to the head.

Another proof of sympathy is the participation in the feelings of others, whose propensity to mirth, or gravity, or to sadness and melancholy, is in a manner contagious to whole companies.

The operations of the imagination, however, as connected with sympathy, are chiefly confined to the body, and, in general, influence only persons of weak minds: hence arise many of those monstrous deformities occurring in the metropolis, but which might have been obviated by a proper exertion of reason, before the fancy was too much excited by the most seductive faculty, namely, that of vision.

The senses receive a sympathetic impression from odious or disgusting objects. Thus, disagreeable sounds set the teeth on edge, and produce an universal tremor or shivering : the taking of nauseous draughts, or other drugs, occasions a shaking of the head and neck. Similar effects arise from unpleasant odours ; and, if a person suddenly withdraw from the sun into the shade, or from a light place into a dark room, an inclination to shudder will be the immediate consequence. - Those readers, who are desirous of obtaining farther explanations of these ideas, will derive instruction from the perusal of Dr. Jackson's Treatise on Medical Sympathy, (8vo. 5s.) - Some, ingenious conjectures on this subject also occur in Dr. Adam Smith's Theory of Moral Sentiments.