PROCEEDINGS OF THE PHYSIOLOGICAL 14 P A convenient form of fluid electrode. By L. W. Collison. (Introduced by H. H. Dale.) The fluid electrode figured is a modification of that described by Brown and Garry [1932], and has the following features which have been found to give additional convenience in construction and use. 0 INCH 1. The instrument is wedge-shaped in section, and this enables the vulcanite plugs, used in filling the chamber with blood and sealing it, to carry the silver electrodes, for which additional openings are not required. It also enables the instrument to be placed in position in a deep fossa, and to take a relatively small length of dissected nerve. 2. The brass holding-rod (H) enables the electrode to be clamped in position. 3. The vulcanite screw functioning as a “grease-gun” greatly facili¬ tates the sealing with vaseline of the hole through which the nerve is drawn into the chamber. The sealing and filling of thè electrode are thus nor¬ mally and easily effected after the apparatus has been fixed in position. REFERENCE. Brown and Garry (1932). J. Physiol. 75, 214.