Keywords: Life in Motion Fig 69.png en Fig 69 ”Arrangement of du Bois Reymond's troughs a a troughs of zinc; b vulcanite plates for insulation; c c paper pads; d e clay pads; f f connections for wires leading to galvanometer g Life in Motion or Muscle and Nervehttps //archive org/details/b21929786 John Gray McKendrick 1892 1926 Life in Motion book Biology experiments |