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

Effects of Electric Currents on the Brain. Dr. Matteucci has made direct experiments to discover the effects of the continuous current of galvanism when applied immediately to the uncovered brain.* For this purpose he em- ployed a good tension current from a compound battery of some sixty pairs. When the poles were applied fairly to the respective hemispheres, he observed that the animal did not start; nor was there any visible effect when the cerebellum was touched. But as soon as the electrodes were directed to the tubercula quadri- gemina and the crura cerebri, while the current was passing, the animal began to scream, and simultaneously all the muscles of the body and limbs were contracted and agitated. As soon as the current was removed, this phenomenon ceased also. .Such are the naked facts, with a constant current. But it would be exceedingly interesting to pursue this subject by experimental research, if it could only be instituted without the objection of solution of continuity of such vital parts. True, Professor Weber has made some interesting investigations into the action of induction currents when applied directly to the brain of living animals, which, of course, are mutilated. But he found no marked effects, even when the sharp electrodes were thrust into any part of the great medullary substance. But as soon as this current was directed through the tubercula quadrigemina, then irregular convulsions are prodiiced, which, he says, very much resemble clonic cramps, and such as are noticed in those patients who are suffering with certain existing disease of the brain. These movements did not appear uniformly, nor yet ir- regularly, in any or all the muscles, but rather in certain groups of muscles which are naturally — or, as we could say, are physio- logically — combined in action, as by reflex influences. If these kinds of currents are brought to bear upon the medvlla oblongata, tetanic convulsions are the consequence, much like those observed in persons or animals when poisoned with strych- * Traite des Phenomenes electro-physiologiques des Animaux, Paris, p. 242. 19*