WATER-BED, called also the HYDROSTATIC BED, or FLOATING MATTRESS. It iS well known that the life and health of every part of the animal body depend on the sufficient circulation through them of refreshed blood. See CIRCULATION. Now, when a person in health is sitting or lying, the parts of the flesh compressed by the weight of the body do not receive the blood so copiously as at other times; and if from any cause the action of the heart has become weak, the interruptiou will follow both more quickly and be more complete. A peculiar uneasiness soon arises where the circulation is thus ob structed, impelling to change of position; and the change is made as regularly and with as little reflection as the winking of the eyes to wipe and moisten the eyeballs. A per son weakened by disease, however, while generally feeling the uneasiness sooner, as explained above, and becoming restless, makes the changeS with increasing fatigue; and should the sensations become indistinct, as in the delirinm of fever, in palsy, etc., or should the patient have become too weak to obey the sensation, the compressed parts are kept so long without their natural supply of blood that they lose their vitality, and become what are called sloughs or mortified parts. These, if time patient survives, have afterward to be thrown off by the process of ulceration, leaving deep hollows to be filled up by new flesh during a tedious convalescence. Many a fever or other disease, after a favorable crisis, has terminated fatally from this occurrence of sloughing on the back or sacrum. The same termination is common in lingering consumptions, palsies, spine
diseases, etc., and generally in diseases that confine the patient long to bed.
It was to mitigate all, and entirely to prevent most of the evils attendant on the necessity of remaining long in a recumbent posture, that the hydrostatic bed was devised by Dr. Neil Arnott, late one of the queen's physicians. The bed may be shortly described as a mattress floating on water, with a loose sheet of caoutchouc cloth properly secured between it and the water, to prevent its being wetted. A person rests on it as a water fowl does on its bulky feathers, with as little inequality of local pressure as if in a bath. A trough of the dimensions of a wide sofa or a bed, having 6 or 7 in. depth of water in it, with the required caoutehouc covering, is the foundation, on which clothes and pillows are laid as in a common bed. A full description is given in Dr. Arnott's book, the Ele ments of Physics (6th edition, Longman SL Co.). The bed not only prevents the occur rence of bed-sores, but by lessening antecedent distress lessens also the danger of the illness.
On a sudden emergency, or when the need of the fluid support is not very urgent, local relief may be given by forming in any way a partial hollow or depression in a bed, and placing in it a water-sack or bag half-filled, so as to remain loose or i slack. This approaches in effect the slack-sided cushion, which is another modification of the n vention.