The prevalence of lowered blood pressure in chronic infections caused us to feel that some of the micro-organisms present in such infections might have properties which lower the blood pressure. The experiments reported were undertaken with this possibility in mind.
MATERIAL AND METHOD
Rabbits were used exclusively in the experiments. Systolic blood pressures were determined in the central artery of the ear according to the method described by Anderson.1 With his apparatus, the obliteration of the central artery was observed through a rubber membrane. With our apparatus, the rabbit's ear rested on a rubber diaphragm covering a pressure cup and a glass plate was adjusted over the ear so that it just cleared the surface without exerting pressure. Thus observations were made through glass instead of through a rubber diaphragm. A detailed description of the apparatus is given elsewhere.2 The mean of a series of five consecutive readings was recorded