Electro-physiology and electro-therapeutics : showing the best methods for the medical uses of electricity / By Alfred C. Garratt.

insensible primary current of galvanism; or graduated to any degree of intensity, even to one hundred elements. And from this one hundred there appears to be obtained quite as much physiological effect, and curative power, as is produced by the ponderous Daniell's battery of fifty elements in quart jars. That is, the fifty or one hundred elements of Garratt's tiny bat- tery, when used either single or double, will accomplish, in ten minutes, about the same that twenty-five to fifty of Daniell's will do in five minutes. Thus, element for element, in these two battery arrangements, the latter has about twice the inworlring power, when compared with the former. But the Daniell's costs five times more than the Garratt's; besides, Daniell's battery is immovable, while Garratt's battery is so compact and clean that it may be carried in the coat pocket, and is always ready for action. The former is best for office and special practice ; the latter for the practitioner's bedside use. To clearly understand the double or twofold action of a Garratt's primary medical battery, as a whole, let it be laid stretched out upon the table, but coiled a little, so as to form a large segment of a circle, as seen at page 154. Thus lying, the poles, or zinc and silver pads, are seen to be a little separated from each other. Now, when any portion of the moist flesh of the human body or limb is embraced between these poles or plates of dissimilar metals, the circle is closed and completed, so that the electric current instantly begins to circulate in a given direction. If, now, the power-coils should be unhooked, and the insulated conductor be directly from silver to zinc, (leaving out the power-coils^) the current is from the zinc through the flesh to the silver, and back again through the insulated conductor to the zinc; so that the zinc pole or plate in this arrangement is the positive pole, while the silver is the negative. Therefore, in order to have the current of the power-coils work in the same direction with the former, the terminal zinc strand of the power-coil must connect with the silver, while the terminal strand of copper, at the other end, connects with the zinc plate. This is important. If, now, the whole is lifted from the table, with one pole in each hand of the operator, the power-coils can be thoroughly wet