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

weight, to pass from the positive into the negative compartment by the end of forty days. Wiedeman, by a series of trials in accurate research, succeeded in discovering the law of this phe- nomenon, and that is, " liquids, when traversed by an electric current, have a very decided tendency to move or flow from the positive pole to the negative pole, provided there is a certain re- sistance to the passage of the electric current." It is well for us to observe that here are found two facts that interest us, and these are — the quantity that is thus transported through a spongy mass in a given time is just in proportion to the intensity of the current employed. This doubtless holds good as a law in physics ; but in relation to the current's action on living sat- urated tissues in the human organism, we conclude the proposi- tion must be somewhat modified. But Wiedeman thought to have determined that the quantity of liquid transported by the power of a voltaic current through a porous partition, as the pipe-clay cup in a Danicll battery, is independent of the extent or thickness of this partition. But M. Do la Rive modifies this by summing up the whole law thus : " The force with which a galvanic current tends to transport a liquid through a porous partition, from the positive to the negative pole, is measured by a pressure which is directly proportional to the intensity of the current, to the electric resistance of the liquid, to the thickness of the porous partition, and inversely proportional to the surface of that partition." Now, as in the decomposition of acidulated water, one equivalent of sulphuric acid goes with the oxygen to the positive pole, while an equivalent of hydrogen is liberated at the negative pole, so the question arises, whether the water thus under the influence of an electric current, and becoming molec- ularly polarized, does not actually present a circumstantial elec- trolytic phenomenon. Electrolysis and Catalysis. —The laiv of electrolysis is this: that a similar quantity, as, for instance, one equivalent of elec- tricity, always decomposes one equivalent of an electrolyte. The law is general, when the combination that is submitted, is composed of only two equivalents, but is modified, in cases where more than one, — and particularly so, where vitalized compounds are the subject of trial. This law is frequently