A NEW BLOODLESS METHOD FOR CONTINUOUS RECORDING OF PERIPHERAL CIRCULATORY CHANGES

¹ Merck Institute of Therapeutic Research, Rahway, New Jersey

1. A method is described by which changes in the intensity of light transmitted through, or reflected from the skin are graphically recorded. This record, combined with a continuous record of the skin temperature, measured by thermocouple, gives information concerning the state of peripheral circulation. During active vasodilatation the intensity of transmitted light is decreased and the skin temperature rises; during congestion the light intensity is also decreased, but the skin temperature remains unchanged or falls; during vasoconstriction the light intensity is increased and the skin temperature falls.

2. The new method can be used not only for the study of vascular actions of drugs, but may also be applied to other fields of pharmacologic and physiologic research; for instance, the evaluation of sensory depressant or stimulating drugs and of local anesthetics. This application is based on the fact that the vessels of the rabbit's ear respond regularly to certain sensory stimuli with vasoconstriction.