Abstract
When freshly defibrinated blood of a rabbit is introduced intravenously into a cat, rat, or guineapig, under urethane, there occurs in the arterial blood pressure two successive falls, the first rather short, usually a relatively small fall, and the second prolonged, usually relatively considerable which starts about forty to fifty seconds after the injection and is accompanied sometimes by bradycardia.
The red cell of rabbit, intravenously injected, causes the second of the same events, and if it be haemolyzed, it causes also a profound fall of pressure, but in the time relation coincides with the first fall. The blood serum evokes only the first fall in the pressure.
Thus, the second, profound fall of pressure is probably due to haemolysis of the rabbit blood in the blood circulation system of cat.
Interference with the suprarenals, splanchnic nerves, vagi, spleen, spleen with the liver arteries and portal vein, or atropine do not affect the appearance of both the falls of pressure.
