A practical treatise on the medical and surgical uses of electricity : including localized and general faradization, localized and central galvanization, franklinization, electrolysis and galvano-cautery / by Geo. M. Beard [and] A.D. Rockwell.

  • Beard, George M. (George Miller), 1839-1883.
Date:
1883
Catalogue details

Licence: Public Domain Mark

Credit: A practical treatise on the medical and surgical uses of electricity : including localized and general faradization, localized and central galvanization, franklinization, electrolysis and galvano-cautery / by Geo. M. Beard [and] A.D. Rockwell. Source: Wellcome Collection.

Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.

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    elongates, and when the charge is discharged it contracts. It is beUevea that the muscle behaves in precisely this manner. If nerves are not affected in the same way, it is because their fibres are not sufficiently elastic. 4. That the blood keeps up the natural charge of electricity in nerve and muscle. The acceptance of this view explains many interesting facts in pathology. It explains rhe fact that diseases that are accompanied by a deficiency in the nerve-currents, as neuralgia, spinal irritation, hysteria, tetanus, epilepsy, usually manifest themselves by morbid activity, by increased and unnatural movements of muscles and nerves. Active inflammations, when there is increase of blood, are not usually accompanied by excessive muscular or nervous action. Apparatus for Studying Animal Electricity.—In a practical work of this kind it is not necessary nor proper to enter into elaborate detail of all the experimental premises by which Matteucci, Du Bois-Rey- mond, Pfliiger, and others have made their discoveries. A very brief description of the apparatus of Du Bois-Reymond may possibly be of interest. He employed a very delicate galvanometer, the distinctive fea- tures of which were, first, the astatic needles were constructed and arranged with great care ; and, secondly, the wire around them was very long, and of from 4,000 to 24,000 convolutions. A multiplier of this sort will indicate the presence of exceedingly feeble currents. The wires of the multiplier are connected with carefully cleaned and pre- pared flat new plates dipped in vessels of zinc, containing sulphate of zinc to prevent polarization. Two cushions, as they are called, made of layers of blotting-paper soaked in a solution of sulphate of zinc, are laid in the edge of each vessel, with their ends in the liquid. The whole is enclosed in a moist chamber. In order to protect any tissue, it is placed in connection with the two cushions in various posi- tions ; then, if there be any current, the deflection is seen in the needle of the multiplier. When two symmetrical parts of the longitudinal or transverse section of a nerve are applied to the cushions, no deflection is seen ; when two dissymmetrical parts of the longitudinal section are! placed on the cushions, the needle deflects 6° or 7°. When the longitudinal section of the nerve on one side touches one cushion, and the transverse sec- tion touches the other side, the needle deflects 15° to 30°. Instead of the galvanometer multiplier we may use the rheoscopic frog, which may give some results ; but it has the disadvantage that it