A text-book of electricity in medicine and surgery for the use of students and practitioners.

  • Poore, George Vivian, 1843-1904.
Date:
1876
Catalogue details

Licence: Public Domain Mark

Credit: A text-book of electricity in medicine and surgery for the use of students and practitioners. Source: Wellcome Collection.

Provider: This material has been provided by the Harvey Cushing/John Hay Whitney Medical Library at Yale University, through the Medical Heritage Library. The original may be consulted at the Harvey Cushing/John Hay Whitney Medical Library at Yale University.

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    CHAPTER X. ELECTRICITY AS A CAUTERY. We have seen that the physician when employing electricity makes use mainly of its specific stimulating and sedative effects upon nerves and muscles. The surgeon also not unfrequently has recourse to electricity for similar objects, but more fre- quently he employs those thermal and chemical effects which the galvanic current is capable of producing. The galvanic cautery consists of a platinum wire heated to redness by a galvanic current. When discussing Ohm's law it was pointed out that when the external resistance was small the inten- sity of the current was increased, not by increasing the number of the elements, but by increasing their superficial area. In the arrangement for the galvanic cautery the external resist- ance is very small—the circuit being closed completely by a metallic arc—and therefore, since the heating power of the current is in direct proportion to its intensity, we use a battery composed of elements of large superficial area and of high electromotor force. The elements are placed as near as possible to each other without actually touching, and the liquids em- ployed have a high conducting power, and in this way the internal resistance is reduced to a minimum. The arrange- ment which is capable of producing the greatest amount of heat is known as Hare's Deflagrator. It is so constructed as to facilitate as much as possible the conduction of the elec- tricity between the zinc and copper plates. It is formed of two very large plates of zinc and copper rolled in a spiral manner parallel to each other upon a central cylinder of wood. The two plates are prevented from touching each other by pieces