(From to lift up.,) to suspend on high. Gestatio, a species of exercise used by the ancients, and of which Aetius gives the following account:

Gestation, while it exercises the body and limbs, still they seem to be at rest. Of the motion there arc several kinds.

1st, Swinging in a hammock, which, at the decline of a fever, is beneficial.

2dly, Being carried in a litter, in which the patient either sits or lies alone. It is useful when the gout, stone, and such other disorders attend, that do not admit of violent motions.

3dly, Riding in a chariot, which is of service in most chronical disorders,especially before the stronger exercise can be admitted.

4thly, Sailing in a boat or a ship. This produces various effects, according to the different agitation of the waters, and in many tedious chronical disorders proves efficacious beyond what is observed from the most skilful administration of drugs. These are instances of passive exercise, and are useful, particularly when active exercise would be improper or impracticable. Asclepiades was the first who brought passive exercise into practice, which was used after severe illness, in order to conquer debility, and invigorate the system by gentle means.

The use of exercise in preserving or restoring health is too well known to require either arguments to enforce it, or regulations to conduct it. The exercises here enumerated, we have said, are passive only; and it is not easy to explain in what manner these can be useful. It may be remarked that all are attended with renovation of the air, which surrounds the body; all require some little exertion to preserve or restore the equilibrium. Dr. Cullen, taking the idea from the motion of a vessel containing a fluid, and observing that the momentum imparted to the latter continued when the motion of the former was suddenly stopped, supposed that the motion of the fluids in the blood vessels continued in the same way, stimulated the vessels, and thus promoted the circulation. The idea was ingenious; but, as the blood vessels are constantly full, we suspect that the analogy cannot be transferred; and the whole advantages of exercise must probably be attributed to the renovation of the surrounding air, and the exertion necessary to preserve the equilibrium. The kinds of exercise here mentioned, are progressive in these respects; and of course adapted to different states of debility. Swinging is a more active exercise; riding and walking progressively more so, and consequently-adapted to the less delicate and infirm.

Other circumstances must, however, influence the choice of our modes of exercise. Sailing has been thought best adapted to hectic cases. The effluvia of the pitch,in the ship, may have some effect, but these could be obtained on shore; and, when this has been tried, no particular benefit has resulted. The sea air is certainly not peculiarly salutary in such cases; though, if the idea of Dr. Rush be admitted, that the mixture of sea and land air is rather injurious than useful, it will account for the disadvantages sometimes experienced from a residence near a harbour. The benefits, therefore, probably result from the exercise, which is constant; the general tendency of the circulation to the surface thus excited, assisted, perhaps, by the nausea. The tendency to the surface is evinced by the constipation of the bowels, and the rare occurrence of catarrhal affections on shipboard.

Riding on horseback has been equally commended in hectic cases by Sydenham, though not confirmed by more recent experience. This remedy is certainly better adapted to the more languid circulation, in the chylopoietic viscera; to obstructions of the liver; bad digestion; and want of appetite. The succussions which the viscera experience by the motion in the horse, must undoubtedly assist the circulation, when languid from indulgence and plethora, or when obstructed from indolence, or the immoderate use of wine and spirits.

Swinging, another remedy for phthisis, should have been mentioned after sailing. It has certainly been of sen-ice: the constant renewal of fresh cool air, for air constantly renewed in this climate must produce cold, checks a too high temperature, and lowers the pulse, while the exercise determines the circulation to the surface.

For preserving health, however, walking is the best exercise: in all the other species, the extremities are not sufficiently warmed, while, by walking, the determination of the blood to the surface is general, every muscle has its share of exertion, and the viscera experience sufficient agitation to preserve their circulation undiminished in force, though perhaps not sufficient to restore it, if the organs are previously diseased.