Plate, arm case used in muscle experiments by Jonathan Goddard Ink diagram showing a metal case designed to receive the arm of a man immersed in water, with a small glass pipe cemented to it at the end in order to measure the volume of muscles in motion. Other versions of this image can be found at RBO/4/95 and RBC/3/170. Subject: Physiology Read to the Royal Society on 16 December 1669. [1669]