We gave on page 107, current volume, an account of some extensive and interesting researches with the great induction coil of the Polytechnic Institution in London, upon the effect produced by lightning stroke on the bodieB of animals, so far as these effects might be considered as indications of death. There are, however, some other characteristic effects produced upon the surface of the body by lightning stroke which are worthy of attention. Dr. Eichardson, the conductor of the experiments referred to, says that several kinds of injuries to the external parts of the body have been described as following upon the reception of severe shocks from lightning electricity. Some of these have been considered by excellent authorities as chimerical,or as vulgarly-exaggerated descriptions of observed, or presumably observed, facts; they have been left up to this time in singular doubt and obscurity. He has, therefore, now that the means of research are at command, investigated this subject with care, and has been able, by a few simple experiments, to place what had been doubtful in a sound and scientific position. The following marks of injuries have been recorded: 1. Marks of burning of the skin and hair. 2. Impressions on the body of metallic substances, such as coins, ornaments, beads, crosses. 3. Ecchymoses, or vivid blue spots, sometimes accompanied with exudations of blood. 4. Impressions on the body of an arbof e8cent kind, supposed to be impressions of trees or fences near or beneath which the person stood when struck by lightningi 5. LOBS of hair, BenjfiM _ ums em the tody from Bgiitoteg e? eteetrteftl steeek are more likely to happen in cases when the person is not destroyed than when the shock is fatal. The reason of this probably is that the burning shock itself is of the flaming rather than of the penetrating kind. The burnings differ in degree; they may be mere singeings of the hair, with superficial scorchings or blisterings of the skin ; or they may be extensive cauterizations leading to surrounding inflammatory action. Metallic substances in the dress, such as pins, stay-busks, buckles, and the like, while they may, in one sense, have their use in directing the shock from point to point over the body to the earth by a superficial route, lead often to severe local injury. In these cases the parts which are burned are those which lie between the metallic points. Corroborative of these conclusions of Dr. Eichardson, we have now before ug an account of a remarkable case of burning by lightning, in the American Journal of Medical Science. The victim of the stroke, was struck upon the back of the head, where she had her hair done up in a knot and fastened by two hair pins. The hair was much scorched, and under the knot of hair the skin was severely burned. Thence the electric fluid passed down, burning the lower portion of the right ear, in which was a gold ear-ring ; then crossed the throat and passed down to the left of ihe sternum. The burn thus produced was about three inches wide, covered with blisters. The fluid here left her body, and finding some other conductor, passed down, still on the left side, to j ust above the crest of the ilium, extending thence forward and backward to the symphysis pubis. This burn was about 12 inches long, and about the same width as the first. The next burn began on the patella of the right knee, extending to the bottom of the heel, in reaching which it wound around the inner side of the leg. The lightning passed off at the bottom of the heel, bursting open the heel-seam of a strongly sewed gaiter boot. The lightning melted portions of the wires of her hoopskirt, also a small part of the lower end of the steel of her corset. The steel clasp of the elastic garter, the steel of her corset, and the metal of her hoop skirt, appear at several points to have carried off the electric fluid. Had the wound been continuous from head to foot, a fatal result would have been inevitable. As it was, however, the lady recovered. Dr. Richardson confirms the popular impression, pretty generally, we believe, discredited by scientific men hitherto, that the impressions of metallic substances may be left on the bodies of persons struck by lightning. He says : " Some years ago an eminent meteorologist of this country forwarded to one of the learned societies the particulars of a case which had been sent to him by a medical man residing in the West Indies. In this case, in which a man was subjected to lightning shock, it was said that impressions of various ornaments were most distinctly left on the body, and, from the manner in which the report was drawn up, it carried with it an air of the strictest probity. The marks, it was said, were of a dark bronze color, and the impressions were so distinct that they could not be doubted. A bracelet or chain was, I believe, stated to be impressed, a coin, and a cross, or similar ornament. On hearing this description, I drew up a short leader upon it, and forwarded the article to the editor of the Medical Times and Gazette, who took it at once to Professor Faraday, soliciting his opinion as to the probability of the occurrences described in the report. Faraday listened with much attention, and then observed, that although he would not like to say the phenomena were impossible, he could see no explanation of them, and, indeed, could scarcely admit the validity of the observation. On this, such was my admiration of the great physicist, I withdrew the essay. In these new researches, however, I have recurred to this subject, and have put the question experimentally in different ways, and now I am bound to say, that impressions such as have been referred to, may be faintly struck on the body. Thus, by placing a thin ring of twisted wire on the ear of a white rabbit, and on discharging througa the ring from the large Leyden battery, there was unquestionably left on the ear a faint blue line showing the position of the wire, the irregularities caused by the twisting of the wire being also distinctly traceable. In the living animal the appearance quickly fades ; in the dead it would of course be left until the organic changes of decomposition removed it. The nature of the mark is very simple ; it is an ecchymosis taking the line of the metal, and so presenting a rough outline of the form of the metal. The shock must be received on a firm surface, such as bone." Simple ecchymoses and livid spots, having no reference to metallic or other bodies in contact with the body, are sometimes presented OH the surface of the body in a very marked degree. Dr. Eichardson affirms that marks on the bodies of persons struck by lightning of an aborescentkind—have been noticed, and have naturally, though wrongly, been supposed to be representations of the figures of trees. To the unlearned such a suspicion is easily conveyed,for the arborescence is described as very perfect, the stem, the larger branches, and smaller branches, as of a tree, being marked out with much refinement. To the learned the suspicion has seemed an absurdity, there being no known physical law by which the picture of a tree could be fixed on the body, in miniature, by lightning. The truth, when explained, is very simple. The arborescent appearance may be fully accepted as a fact, and as having been observed in cases of lightning shock; but the arborescence is not the figure of a tree ; it is an anatomical outline of the trunk and branches of superficial veins of the body of the subject. More than one hundred and ten years ago, the fact that the veins could thus be penciled Out by lightning discharge, was fully described by the illustrious Beccaria, who states minutely that ft man struck dead by lightning in a storm was left generally rigid, and exhibited this added .nd feus-Sous pfe_om6Ro! TJt* lightning) s_oig the bs mw ductor, having struck a vein in the neck, and followed i t out to its minutest ramifications, the figure of the vein appeared through the skin, finer than any pencil could have drawn it. In order to test this explanation Dr. Kichardson directed a charge from a Leyden battery through the ear of a white rabbit, from a large trunk of a vein at the base, and in the line of the center of the ear, to the extremity of the organ. One discharge was in this experiment quite sufficient to bring out the figures of two large veins, which appeared like pen marks on the surface. He says : " Blood in these cases undergoes arrest of its motion, expansion, and possibly decomposition, by which some of the coloring matter is liberated. Thus, the vulgar observation of arborescent marks on the dead after lightning-shock admits of recognition by the most critical, and of explanation by the most simple of scholars. It is often thus that the illiterate, correct in what they have seen in nature, appeal in vain to science, because, impelled by the strongest of all instincts, reason, they connect their facts with some theory of cause which science proclaims to be untenable, and dismisses alike fact and theory with hasty contempt." The loss of hair as one ot the sequences of lightning stroke Las also been confirmed by these experiments.