sions in mines, and of a very fatal character; also 77 compound fractures; 201 cases of diseased joints; 33 of lead poisoning; 14 of strangulated hernia; 13 of vesical calculus. The burns alone would probably make a difference of more than one per cent. By a rule of the Infirmary, no one can be admitted as an in-patient who may as well be relieved as an out-patient. Hence the cases of chickenpox are N. S. 0, V. 110; sore-throat, N. S. 27, V. 301; headache, N. S. 0, V. 61; gout, N. S. 4, V. 140; with respect to peritonitis (27), pneumonia (46), pleurisy (15), and bronchitis (207), the numbers confirm Dr. G.'s remarks. We may also finally inquire how it is that out of more than 6,000 patients at the Vienna Hospital, there were but five of paralysis, and the same question may be asked with regard to other serious diseases, as malignant tumours. Such a statement, if it does not arise from the diseases of the patients being of a very minor degree of severity, is contrary to the laws of disease, and we hence conclude that homoeopathic practice is a bagatelle, and that very few with serious diseases are so weak as to trust it. To deny that in Mesmeric passes there is proof of any fluid or agent, electrical or magnetic, or of any influence whatever passing between the magnetizer and the patient, does not entail upon us the necessity of denying that a true electricity exists in animals. It has often been witnessed in human beings under the form of sparks, passing between the body and external objects, and man requires only to be isolated for it to be manifest at any time by means of the galvanometer. Electrical fishes are a well-known instance. also in point, the electricity in their case exhibiting all the usual characters which it ordinarily presents. The electrical state of the atmosphere evidently affects the cerebro-spinal system of some individuals, and the chemical actions and changes of form going on in the body must produce electrical disequilibrium, as we may see out of the body in chemical operations, or in the rising of steam from the cap of the gold-leaf electrometer. But electrical disturbance is manifested in animal bodies in a more curious and interesting way, and principally as connected with the muscular and nervous tissues, and a new science has arisen consisting of this class of facts, originated in the discoveries of Galvani and Volta, with respect to the curious contractions which take place in the muscles of a frog, when its nerves are manipulated upon, so as to disturb their molecular electrical state. If we lay bare the sciatic or crural nerve (Plate IX. Fig. 7), and touch two points of it, or of nerve and muscle, with dissimilar metals, zinc and copper, or, still better, zinc and silver, or gold, the metals themselves being in contact at one point, or at least joined by a conductor, convulsions take place, particularly upon closing the circle, and especially if the nerve is electrified peripherally, or in the regular course of the so-called nervous. fluid: if, in the contrary direction, very likely at opening the circle. The metals need not touch the nerve except mediately, as through another separate semicircle of nerve touching the first at the ends, and itself electrified by the pieces of metal ;* or two individuals may hold the limb of the frog, the one by the nerve and the other by the toes, when, holding the metals in the other hands, and making them touch, convulsions take place; if, however, the little fingers of these two hands be moistened and brought in contact, no contractions happen, the electrical disturbance taking place, of course, in the shortest circle. These experiments only rank with the well known effect on the optic or lingual nerve, when we connect pieces of zinc and silver, the one placed above, the other below the tongue. Volta's discovery of the galvanic pile, &c., nipped in the bud this interesting branch of practical physiology, as it was at first overlooked that metals were not necessary at all to produce contractions. It may be easily shown by placing one end of the frog's prepared extremity in a glass of salt-water, and the other in a second, that contractions take place on connecting the two glasses *This was, perhaps, an electro-tonic effect. by a piece of moistened lint, without the use of any metal. This, and other experiments, as those of Humboldt, in which contractions took place on simply touching the muscle with the nerve, or connecting the nerve and muscle by another piece of animal tissue, are very interesting, as proving the existence in the nerve and muscle of animals of spontaneous electrical currents. If contractions are produced in a frog's limb, secondary or induced contractions may take place in a second one, having its dissected nerve placed in the muscle of the first; the molecular derangement of the one causing a similar state in the other, according to the well known laws of what is called positive and negative electricity. M. du Bois-Reymond has investigated the law of electrical manifestation in detached muscles and nerves: the longitudinal surface being always positive in respect to the transverse. (Plate IX. Fig. 6.) Nobili, Mateucci, and others, have also advanced this branch of science. The discovery of Ersted of the effect of a current of electricity around a neighbouring freely suspended magnetic needle, has not only originated the electrical telegraph, but furnished the physiologist with an instrument (Fig. 5), the galvanometer, which may be made by means of the astatic needles, &c., of extreme susceptibility, and in M. du Bois-Reymond's hands, has elucidated the laws of this animal electricity. The convulsions produced in the limbs of frogs do not take place simply from the amount of electrical fluid, to use so incorrect a term, present in them, but only in consequence of disturbing their electrical equilibrium in breaking or completing the circuit. When electricity acts on the sensuous nerves, as in the experiment of the zinc and silver placed in the mouth, the effect is continuous. It is proved that in sensuous nerves the electro-motor action can be produced peripherally or centrally. A nerve electrified in any part of its course has its electrical state altered, or polarized, throughout the whole of it, called its electro-tonic state. M. du Bois-Reymond produced an effect on a delicate galvanometer by the contraction of his arm; but this, and other contractions, do not produce an increase in the effect on the needle caused by the previous electro-motor state of the muscles, but the reverse-á negative deflection in the opposite direction, or rather, perhaps, a cessation of effect, as the small opposite deflection beyond zero may be accounted for by extraneous causes. The total current produced by the electrical state of the different muscles of animals, appears to vary in direction in different species. : The nervous force, in some respects, presents us with an analogy to the electrical, in others it evidently differs from it sensitive and motor nerves are very easily excited by weak electricity, as is well known; the nervous circle is also very like the electrical one; so also the structure of the encephalon most resembles a galvanic arrangement. On the other hand, other stimulants have a powerful effect in exciting sensations and motor impulse in the nerves, and appear analogous to that of electricity in this respect; no increased action has ever been produced in the galvanometer by connecting it with a large nerve in a state of active excitement, but we may infer the reverse from what has been already observed, the nervous impulse appearing to destroy the natural electrical state; the conducting power of a nerve is not at all identical with that of an electrical wire, a ligature round a nerve stopping the nervous force, but not that of electricity; neither can an electrical conductor be made to take the place of an excised portion of nerve, as far as the nervous impulse is concerned, but only as regards electrical action; nerves, too, are bad conductors of the latter; and the velocity of nervous impulse, and that of electricity, appear to be widely different.* The nervous is the vital power par excellence, in relation to, but not identical with, the great physical forces, electricity, magnetism, heat, light, &c., one frequently determining the development of the other. * Valentin's Text-Book. |