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

always advance, pari passu, with the occasion of their agitation ; that in certain constitutions, the effects occur several months later than in others ; that when the epidemic has set in, after the waves of positive or negative electricity had passed over or through a place, the epidemic has mani- fested itself long after the terrestrial or atmospheric condition of the dis- trict had been restored to a neutral state; either by the equalizing power of the thunder between plus and minus clouds, or by both these being blown away by currents of the air. 37. That it is only by careful atmospheric, and telluric examinations, we can learn the advent and cause of epidemics before their invasion ; and that after they appear we may sometimes find the electricity of the situation restored in its due quantity or balance. 38. That from twenty years' practical experience, in a meteoric and marshy district, I have concluded that, as electricity in all probability is heat, or the active cause of heat, its laws hold similar relations to those of caloric. That, as cold is the absence of heat, the same electrical ratio applies to cold also; — that as water boils at 212°, strong nitric acid at 248°, oil of turpentine at 314°, sul- phuric acid at 620°, and mercury at 662°, — so certain steps of electrical alterations, or disturbances, will reach certain peculiar epidemic consequences, or points. Each particular step produces its own particular results, in suscep- tible persons ; and sooner or later, according to their aptitude or susceptibility. 39. That, as we are taught by experience, some people are scarcely liable at all to impulses of galvanic inequality ; some are very slightly so and others slowly affected, or only after long intervals. We have also seen, that some persons escape altogether the shocks or oscillations of galvanic passes ; others slightly feel their premonitory signs, or symptoms ; whilst some withstand the concussions or derangements for weeks, or months. I cannot believe that similar differences would result, were marsh miasms, or poisons, (inhaled by breath,) the exciting cause; such active poisons, if in existence, and capable of destroying strong men in a few hours, would bring every human being within their reach under their destructive sway, without omission or delay. 40. That as free electricity very generally prevails in the air of most places, it may be asked, why cholera in man, and blight in vegetables, do not com- monly prevail at all times. To this I reply, that the integuments, even of delicate human beings, are not susceptible of ordinary or slight electric passes, unless the part be moistened. The whole surface becomes moistened in hot climates by the dew at night; and hence I think that cholera or agues invade people at night, particularly towards morning; as we know that negative elec- tricity reduces men in the rice lands of Italy to the most awful state of dis- order. But were the cause, as said to be, miasms, extracted from fens by the heat of the sun, their lethal violence would, on the contrary, assail all persons by day. As multitudes labor in the fields by day, multitudes would fall by poison ; but thousands escape the pest, provided they do not sleep in the air, or on any ground floor by night. 6