STUDIES ON INFLAMMATION : II. A MEASURE OF THE PERMEABILITY OF CAPILLARIES IN AN INFLAMED AREA

1. By means of a colorimetric method the concentration of trypan blue in capillaries can be estimated by direct observation and its changes followed as the dye passes out of the circulating blood stream. 2. The change in concentration of trypan blue in the capillaries of both the normal and the inflamed mesentery of frogs can be described by two separate exponential equations of the type: y = be^-ax. 3. From these equations it is found that the rate of fall of concentration following intraventricular injection of the dye is almost twice as great in the capillaries of the inflamed as in those of the normal mesentery. This difference is a measure of increased permeability with inflammation.