The Factors Concerned in the Appearance of Nucleated Red Blood Corpuscles in the Peripheral Blood

Abstract

During the winter of 1915-16, while developing a method for isolating the circulation through the tibia of the dog (1), two of us became interested in the active vasomotor control which the vessels of the marrow were shown to possess. At this time we undertook to determine what factors of coagulation (2) arose in the bone marrow, and in order not to complicate conditions physiological salt solution, Ringer's solution, and physiological salt solution containing small amounts of sodium oxalate were used as perfusion fluids. These solutions were delivered to the bone by means of a simple constant pressure apparatus and though usually oxygenated as thoroughly as is possible with such fluids, still it must be considered that they were relatively oxygen-free. Under the conditions of the experiments it was found at once that various characteristic marrow cells appeared in the effluent. Thus, nucleated red blood corpuscles, occasional myelocytes, and even at times megakaryocytes could be identified. Our attention was directed to the question of cellular egress by the observation that vasoconstriction, produced by the addition of small amounts of adrenin to the perfusing fluid, resulted in instant diminution of the number of cells leaving the marrow, and with the characteristic vasodilatation which concludes the reaction a large increase in the number of cells was noted. These findings paralleled those made