On an electrical bench for physiological research / by R. Milne Murray.
- Murray, Robert Milne.
- Date:
- [1891]
Licence: Public Domain Mark
Credit: On an electrical bench for physiological research / by R. Milne Murray. Source: Wellcome Collection.
Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.
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![considerable moment to one working in a private laboratory, and it is probably chiefly by such that its advantages in time and trouble saving will be specially appreciated. The various parts of the apparatus are flxed to a table made of well polished butternut; the connections between the various keys relays and terminals being made by properly insulated tinned copper wires which pass through and run from point to point under the table. The rate of interruption of the current (and of consequent stimulation) is determined by the vibrations of a reed A (Plate II.), whose length and period can be altered by means of an adjustable clamp B in which it is held. A platinum point attached to A dips into the mercury cup C, and closes the circuit of the battery E through the magnet D. This pulls the spring out of the mercury, breaks the circuit, and the spring falls again into the mercury. In this way the reed is kept vibrating at a rate determined by its length between the clamp B and its free end. The details of this part of the instrument are shown in Plate III., fig. 1. If the block F be ]Dlugged, the circuit is confined to the spring and the magnet. But if F is unplugged, then the current will pass round GGG. If, now, any of the blocks H^H2H3H4 be unplugged, the circuit will include the magnet of the relays S,I,K or L respectively. Let be unj^lugged, then the relay S will repeat the vibrations of the spring, and, closing the circuit of the battery N, will actuate the time-marker T, which will record the number and rate of the vibrations of the spring on the drum V. Now, let the block Hg be unplugged, the relay K will then act and make the circuit of the battery Ng, which includes the primary coil P of a Du Bois Reymond induction coil. This will induce currents in the secondary coil R, and so excite the nerve-muscle preparation W, whose contractions will be recorded by the lever U, immediately under the markings of the signal T. Thus the rate and moment of stimulation will be recorded by T, while the result of that stimulation will be recorded by U. Similarly, if H2 be unplugged, the relay I will close the](https://iiif.wellcomecollection.org/image/b24930131_0004.jp2/full/800%2C/0/default.jpg)
