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

being confined to a line directly between tbe placing on of the two poles. He found that single shocks produced no influence upon it. Guided by these results, Dr. Mackenzie has employed electric currents, in several very critical cases in obstetric prac- tice, with remarkable success. Effects of Electric Currents on the Heart and Blood Vessels. If we examine the heart of an animal immediately after death, as soon as the heart has ceased to beat, we see that the electro- magnetic current brings back the rhythmatic contractions. But the phenomena produced by applying the electric stimulus directly to the heart differ according to the part of the heart so touched. The contractions are uniformly more marked in the right than in the left ventricle; for after death, the left ventricle is usually found firmly contracted upon itself, and is more in- sensible to the stimulus. But the right ventricle is almost always surcharged with blood, and this contracts very beautifully when touched with the electrodes. If the animal is killed by chloro- form, then sometimes the left ventricle is observed to be still con- tinuing to pulsate a very little, while the right ventricle is entirely still, and largely distended with black blood. It is found that if the right ventricle be electrized in these cases, its contents are expelled, and its rhythmatic pulsations are soon restored and established. We said that different phenomena are observed from touching different points of the heart. If we arc reminded, however, that the heart is animated with two peculiar sets of nerves, we at once comprehend the wide difference in the effects. The heart's nerves are, first, the ganglionic, and, second, the vagi. The gan- glionic or sympathetic is its motor, and the vagi is its regulator. If the former is electrized, the contractions of the heart are augmented; if the latter is thus acted upon strongly, then the pulsations of the heart stop. Besides the above facts, first ob- served by Professor Weber, of Leipsic, there are very many other instructive results obtained from electrizing the vagi, which were, indeed, mostly discovered by M. Claude Bernard. He found,