This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol1", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
For medical purposes electricity is developed or excited in four somewhat distinct methods; 1. by friction, in the form of common electricity; 2. by contact and chemical reaction, in the form of galvanism; 3. by magnetic induction, in the form of electro-magnetism; and 4. by a combination of magnetic and galvanic induction, as by the volta-electric apparatus.
 
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