The Effects of Serum Treated with Agar

The intravenous injection of horse serum, kept for 2 hours at 38 degrees C. in the presence of one-fifth of its volume of a suspension of 0.5 per cent agar in physiological salt solution and then separated from the agar by centrifugalization and filtration, produces in normal rabbits in adequate doses a considerable and prolonged fall in the blood pressure, expulsion of feces, a diminished coagulability in the carotid blood, and at times accelerated respiration; that is, the various symptoms observed after the intravenous injection of horse serum in a seroanaphylactized rabbit. Horse serum previously kept for 30 minutes at 56 degrees C. and then treated with agar in the manner described above, when injected intravenously into a normal rabbit will have no more effect on the arterial pressure, on the intestinal movement, on the respiratory rate, or the coagulation of arterial blood than the introduction of horse serum into the veins of a normal rabbit.