Transfusion of Blood, an operation by which that fluid may be conducted from one animal body into another.

This singular and daring attempt was first undertaken by Libavius, at Halle, early in the 17th century : he recommended experiments to be made on calves, sheep, dogs, and other animals. After these had been successfully performed, a whimsical notion of prolonging human life, by the practice of transfusion, was publicly maintained, with almost general approbation by Lower, in England ; Hoffman, in Germany ; Denis, in France, and other bold physicians. But, when several persons unfortunately fell victims to such experiments, the flattering prospect completely vanished, till the late John Hunter resumed the subject, and treated it in a manner peculiar to his penetrating genius.

In performing the process of transfusion, the vein, which is usually chosen for blood-letting, was opened, and a quill, or other tube introduced in a perpendicular direction: the corresponding vein was then pierced in a healthy person, or more frequently in robust animals; and a similar tube was accommodated to the orifice in a slanting way 3 both tubes were then passed one into another, and thus the blood was gradually transfused 3 the vein being tied up, as is usual after venese6tion.

This operation is certainly ingenious ; but, as it requires equal judgment and dexterity, we doubt whether it will ever become an useful branch of the healing art, in the present state of society: nay, it appears to us, that it cannot be performed with safety, since the introduction of the late inoculations, excepting in very desperate cases, such as hydrophobia, or other internal poisons, in which the whole mass of the blood is in a dissolved or tainted state. Besides, this essential fluid is, in every person, of a peculiar nature adapted to his own constitution ; and consequently cannot, with reasonable hopes of success, be transfused into another; hence the visionary idea of renovating the animal spirits by-artificial means, and of prolonging human life beyond the period appointed by Nature, must necessarily be defeated. - See also LifE, Longevity, etc.