"It was hoped that some light might be thrown on the length of life of normal blood corpuscles and the mechanism of their removal from the circulation by the study of the elimination of transfused blood, which it is possible to make when the transfused blood is of a group unlike that of the recipient. This study has brought to light two facts, first, that the length of time that transfused blood remains in the circulation varies greatly; and second, that the elimination is not a continuous process but takes place in more or less cyclic crises, so that the circulation seems to rest more heavily on this cyclic activity of the body than on the condition of the corpuscle."