Laundering the Blood

When the blood in a man's body becomes fouled, it may be possible to remove and wash it, like linen. A remarkable device to accomplish this is being perfected by Dr. John J. Abel, distinguished pharmacologist of Johns Hopkins University. It is, in effect, an artificial kidney, an external laundry for the blood. The purpose of the apparatus is to extract foreign substances and mineral poisons from the circulation by tapping one of the large arteries, passing the blood through a purifier, and returning it to the heart by reinjection in a vein.

As simple as this is in principle, the method is complicated in procedure by many difficulties: 1) What is to be put back into the body to take the place of the missing blood? A salt solution properly proportioned -the "normal saline solution" frequently injected after hemorrhages -can act as substitute for a considerable quantity of blood. A balanced amount of this is contained in the tube of the artificial kidney so that the blood, entering, pushes the solution ahead of it into the vein at the receiving end. 2) How is the blood to be cleansed without any halt in its passage through the tube? By the substance of the tube itself, which is made of a porous material called celloidin. This is permeable to certain solids, among them mineral poisons, which it absorbs as the blood flows through ("Dializing out" is the stock laboratory idiom for this method of removing impurities). 3) How can substances necessary to the blood be prevented from escaping through the porous tube? They cannot be prevented, but identical substances in compensating amounts are dissolved in the surrounding solution so that the blood can lose nothing that it is desirable for it to maintain.

Dr. Abel has not yet used his invention in human experiment. It has been employed with considerable success on dogs and a few larger animals. Until it is perfected, the usual doubts abound.