Plethysmograph
From BiblePortal Wikipedia
Plethysmograph [1]
(n.) An instrument for determining and registering the variations in the size or volume of a limb, as the arm or leg, and hence the variations in the amount of blood in the limb.
Plethysmograph [1]
(n.) An instrument for determining and registering the variations in the size or volume of a limb, as the arm or leg, and hence the variations in the amount of blood in the limb.