TRANSFUSION OF BLOOD is the operation of transferring the blood of one animal into the blood-vessels of another, and is sometimes beneficially employed for reviving those who are nearly dying after severe haemorrhage. The operation had long been used as a means of experiment, and in the vain hope that by injecting the blood of a healthy man or animal into the vessels of a diseased one, the health of the latter would be restored ; but it had rarely been employed fur its only useful purpose till Dr. Blundell, after a long series of well-con ducted experiments on animals, proved that it might be safely and advantageously employed in men. His observations are published in his' Physiological and Pathological Researches ;' and since hie revival of the operation, the lives of many persons have been saved who were, in all probability, dying from the loss of blood during or after operations, during gestation, and in other circumstances. The opera tem has, indeed, often failed ; it has often been unuccesa-u-ily per formed ; and its performance is not unaccompanied by danger to the patient ; but still there is eufficient evidence of its high utility in cases which, without it, would have been quite or nearly hopeless, to warrant its being resorted to under the guidance of a sound judgment.
The chief instruments employed in the operation are a syringe, with double pipes, a basin of appropriate form, and a fine tube fixed on one of the pipes of the syringe. One of the veins of the arm of the patient being opened just sufficiently to admit the point of the tube, and fixed by a probe, blood meat be drawn through a free opening in the vein of some healthy person, and as it flows into the basin must be slowly sucked up, without any mixture of air, by the syringe. When the
syringe is filled and carefully cleared from all sir by forcing blood up to the very point of the tube, the latter must be introduced into the patient's vein, and the blood steadily and slowly injected. Four or five ounces are often sufficient to revive a patient, and if they produce headache, fluallings of the face, tendency to fainting, and other unplea sant symptoms, the transfusion should be arrested ; but if not, the injection should be continued till it produces some good effect, or till a pint of blood has been transfused. Beyond this it is not safe to carry the operation, nor is it likely to be beneficiaL A second or a third injec tion may be employed when the state of the patient seems to render it necessary.
The experiments of transfusing the blood of various animals into the vessels of man proved only mischievous; and those of transferring the blood of an animal of one species to the blood of another species Are of too little interest and have produced too few general results to be worth recording here. The injection of various medicinal substances into the veins has been tried, but its effects are not sufficiently differ ent from those produced by the ordinary mode of taking medicine, to render it advisable to submit to an operation which is itself dangerous. All the important facts relating to the subject may be read in an article on Traniduaion, by Dr. Kay, in the ' Cyelo1sedia of Practical Medicine,' and in the works from which he quotes.