STUDIES IN ASTHMA. VII. THE PULX~ONARY CIRCULATION IN TIlE GUINEA PIG DVRING

In 1924, Drinker and Bronfenbrenner (1) measured the pressure in the pulmonary artery of the rabbit, the cat, the dog and the monkey during and for a brief period after the intravenous injection of small doses of sheep serum. The animals in question had received antecedent doses of this protein. I t was found that in rabbits, anaphylactic shock is characterized by a notable degree of pulmonary vasoconstriction, great enough in some instances to cause the death of the animal. The same reaction but in lesser degree was observed in cats. Shock in dogs was wffhout expression in the pulmonary circuit and as has been the invariable experience; no gross phenomena of any sort followed the second injection in monkeys. At the time these experiments were made, measurement of the pulmonary arterial pressure in the guinea pig under good physiological conditions had not been accomplished. During the past spring the authors (2) have devised a method for making this measurement, which is so simple and reliable as to induce them to carry out the missing experiments upon this animal. Auer and Lewis (3) in their paper on the immediate reaction of anaphylaxis in the guinea pig measured the systemic blood pressure during "shock" as have also Anderson and Schultz (4) and Loewit (5). All these authors have shown a rise in this pressure, coincident with the development of asphyxia. The absence of pronounced changes in the action of the heart constituted presumptive evidence that