Medicine: Sheep’s Blood Bath

When the medical world was agog over the discovery that blood circulates through the body, imaginative surgeons tried to transfuse sheep’s blood into human patients weakened by too generous bloodletting. Since they had never heard of such things as protein compatibility, it is small wonder that most patients died. In 1678 the French Parliament banned transfusions. Nowadays, no doctor would dream of transfusing animal blood to man. But last week, the medical world was again agog over a report that Italian physicians had used a sheep’s blood to help clear the system of a woman dying of mercury poisoning.

In London’s medical journal Lancet, Professors Michele Pavone-Macaluso and Antonino Anello described the case. Last winter a 34-year-old housewife bent on suicide swallowed bichloride of mercury. After eleven days, her system still could not flush out the poison. So with tubes from a vein and artery in one arm, the doctors hooked her up to an artificial kidney. But instead of letting her blood circulate through cellophane tubing in a chemical bath, and relying on the solution to remove the poisons, they wheeled a donor into the treatment room. The donor: a 130-lb. ewe, heavily draped to conceal its identity. From a neck artery and vein the doctors hooked up the ewe to another cellophane tube. This was wrapped around the tube through which the patient’s blood circulated, and the two rested in a plasma solution to serve as an intermediary in the exchange.

The Sicilian doctors’ reasoning: a chemical cleansing bath is better than none, but it lacks so many of the factors usually found in blood that the patient loses some substances that are essential to life. Cellophane tubes of the type used in the artificial kidney will stop big protein molecules, so there should be no danger of a fatal antibody reaction. But they allow the blood’s complex chemicals to pass freely if they are fully dissolved. So the protein-free part of the woman’s poisoned plasma passed through both tube walls and into the sheep.

This “dialytic parabiosis” lasted 90 minutes, was credited with helping to save the woman’s life. (The sheep also recovered after a brief feverish illness.) Last week Dr. Pavone-Macaluso said that he wanted to try the technique again, but with a bigger donor animal—and hence a larger blood volume—to clear the patient’s blood faster. In fact, he said, if he could figure out a way to get it into the operating room, he would like to use an elephant.