Electro-physiology and electro-therapeutics : showing the best methods for the medical uses of electricity / By Alfred C. Garratt.
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sudden, and unpleasant sensation, which we term the electric shock. The strength of this shock is mainly in direct ratio to the extent of the metallic coating of the jar, and to the degree of high intensity with which that is charged and the suscepti- bility of the patient who receives it. This may be transmitted through one person, or even through a great number of persons in a chain, if the first person takes hold of the recently charged jar near its bottom, while the last person in the circle then touches with his finger the knob or ball on the top of the jar, and while they all hold each other by the hand. If several jars are properly united and fully charged, they might give a shock through the human body, by its action on the nervous system and the natural animal-currents that would exhaust them to such a degree, that it might prove as fatal as lightning itself. The discharger is a nccessaiy accompaniment of this machine, which consists either of stationary or adjustable metal arms, tipped with brass balls, and provided with a long glass handle. I find that two of these dischargers are more convenient than one, as for making discharges through the pel- vis from the sacrum or lumbar region to the top of the pubis, in cases of dismenorrhcea. But it is necessary to approach the charged Ley- rig, e. <jen jar wjftj jjjg ]jrafS balls of the discharger always in one order; and that is, first make a ball to come in contact with the outside of the charged jar, before the con- tact is made with the knob on the top of the jar; for if the machine works well, and the reverse order is carelessly taken, i. e., to touch the top knob first, and then the outside of the jar the last, it will be very likely to break or to be perforated, and thus spoil the jar for further use. Another condition already alluded to, is necessary to succeed the best possible in charging a Leyden jar — for in medical practice but one or two at most are ever wanted. The outer foil of the jar must be in communication with the conductor to the earth, so as to utterly dissipate the negative electricity from outside the jar while it is being charged inside positively. But I must here take space