731 employing alternating currents errors also crept in, owing to the electro-chemical or voltametric capacity of the human conductor. The resistance of a St. Thomas's Hospital porter's tissues by using the alternating currents was determined with the aid of a galvanometer and found to be 1160. But polarisation setting in causes usually a steady rise in the resistance ; chemical decomposition taking place inside the body develops an opposing electro-motive force. Dubois-Reymond asserted that he

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... had not taken the trouble to ascertain the human resistance, but Dr. Stone believes that he really gave it up in despair owing to his obtaining such variable results. The lecturer said that at the suggestion of Dr. 0. Lodge he had adopted Kohlrausch's principle, the apparatus consisting of an induction coil and telephone. This will be explained in another lecture. Reference was next made to Sir Henry Alance's method of measuring resistance; this eliminated the errors due to polarisation and electrolysis. The body might be regarded electrically as a faulty submarine cable; it was for this that Mance employed his method, but Dr. Stone now used it for investigations on the human body. It appeared that Mance had already made a few observations, and actually determined the resistance of the human living conductor at 900 to 1100 ohms. Rosenthal's estimate of 8 to 20,000 ohms was much beside the mark. In Mance's method a modified Wheatstone bridge was used ; it allowed polarisation to do its worst. The following simple formula showed the method of estimation of resistance :-It was ascertained by experiment on the porter that the resistance rose 7 ohms from polarisation, and Dr. Stone stated that, as a rule, the resistance increased whilst the current was passing through the body. Some observations had been made by other investigators and at different times than those of his own-especially Mr. Lant Carpenter; and it was interesting to note that the results were practically the same, though different kinds of apparatus had been used. Thus with an electro-motive force of 2 volts the resistance for the first minute was found to be 1194 w, but at the fourth minute 1230 w; with 4 volts at the fourth minute, 1155 w; with 8 volts (Dr. Stone) the first minute gave 1130 w, the fourth minute 1160 w. It seemed clear, then, that the human resistance was much less than had hitherto been supposed. Further, Dr. Stone found that if the patient had been in sound health the size of the individual made no difference, as the table already given shows, where, if anything, the smallest man gave the highest resistance. As is the length of the levers of the body so is the sectional area of the muscles that move them. He would not assert, however, that the law was universal. In disease considerable differences obtained. Mr. Cunynghame had taken the resistance of the human body as 2000 ohms, with a view to determine the real limits of safety for electric lighting, and this was a difficult matter. Accidents happened with powerful dynamos, but it was almost impossible to ascertain their frequency or anything about them; they were seldom made public, and generally hushed up, probably because it was thought by the promoters of electricity for useful purposes that publicity of the facts relating to accidents might interfere with the future success of the industry. Dr. Stone next considered a few of the alterations in resistance that occurred in certain diseases. The point was not yet settled whether the human body acts as a solid or as a fluid conductor; the behaviour of iluids and solids to heat showed that there was a considerable difference in their molecular structure. In his opinion the tissues did not act as fluid conductors. It was ascertained that dropsy enormously reduces the resistance. It sank to one-half in one case which Dr. Stone had the opportunity of investigating before and after the appearance of dropsy; this did not seem as if muscle acted as a fluid conductor. In fact, muscle was more resistant in good condition than when replaced by connective tissue. The lecturer had investigated six cases of very old hemiplegia ; the difference of resistances respectively between the scund aid diseased side were 420, 350, 360, 120, 550, and 730 -results so different from the normal 1000 that he considered them as not to be explained by mere accident. Certain cases of impregnation of the body by metallic impurities were also ascertained to alter considerably the resistance to the passage of electricity Thus in a case of mercurial intoxication there was a considerable increase in the conductivity of the tissues, which was not so marked in lead-poisoning. In a case of impregnation by copper, where the right hand was most affected, it was found that this hand gave less resistance-was, in fact, a better conductor than the left. The urine in this case was decomposed by electrolysis and 3 milligrammes of metallic copper obtained. As to the influence of pyrexia, Dr. Stone quoted some results, which have already been published in Nature, in a case of ulcerative endocarditis; the general result, which requires confirmation by further observations, was to the effect that the resistance in fever is greatly decreased. MR. PETEU, GOWLLAND had operated for some anal trouble upon a gentleman who was staying at an hotel in Finsbury. The wound had healed; it had been only a small incision, not confining the patient to bed. At the time of the operation ether was administered, and it was noticed that a great deal of ether was required to produce full anaesthesia, but beyond this no signs of any unusual occurrence were observed. Three weeks after the operation the patient was found dead on his bed. The body was naked, already cold, and in full rigor mortis; it was twisted as in suffering, the face turned to the pillow. A light was burning in the room, the time being near midsummer. From all the circumstances it was evident that the deceased had been seized with sudden illness, and had died as he was undressing for bed. A brother who had been a good deal with him in the last few months said that there had been no complaint made by him. A servant at the hotel had seen Mr. Gowlland's patient go upstairs to his bedroom about 11 P.M. on the night of his death, and had noticed the alacrity with which he ran up the stairs; she remarked that he appeared to be an active, vigorous sort of person, in good spirits. On inspection, seventeen hours after death, the body was well nourished and younger looking than the stated age. There were no signs of decomposition. The examination discovered nothing whatever of a morbid nature except in the vascular system. The state of the heart at once drew attention. Its left side, especially the ventricle, was much distended with liquid blood, the right cavities being distinctly less loaded than usual. The substance of the heart was very soft and flabby, although rigor mortis was strong in the trunk and limbs. The endocardium and endarterium were stained red, showing that the red blood-corpuscles had partially disintegrated since death. The relatively empty state of the right heart, taken with the distended condition of the left, proves that the cause of death had not been any kind of obstruction to respiration, but was due to failure of the left ventricle after the left auricle had acted. Death was due to syncope in cardiac diastole. On proceeding to examine the heart more narrowly, the course of the coronary vessels could be traced with the finger, these arteries feeling like threads of stone in the rather considerable amount of fat which followed the lines of the inter-ventricular grooves. The inside of the aorta was found, on the other hand, to be in a good state of preservation for the age of the individual. There were but a few patches of quite supernoial degeneration, and these did not implicate the mouths of the coronarv arteries, which were of normal size, readily admitting n ordinary probe. But on opening up the left coronary artery with a fine pair of scissors, its walls crackled and broke, with a fractured stony edge, and this went on as the course of the vessel was followed until reaching about two-fiflhs of the way down towards the apex of the heart. At this point the channel of the vessel proved to be partially obstructed. Q3 J .