Mr. Bickersteth’s reason for attributing the stoppage of the pulse to the effect of the knife, rather than the chloroform, was that he had arrived at the conclusion from some experiments which he performed on animals, that the action of the heart cannot be arrested by chloroform, until the breathing has been first suspended. One of Mr. Bickersteth’s experiments (No. 5, on a half-grown cat) exactly resembles the experiment (No. 28 in this work) on a rabbit, which I had published upwards of a year before Mr. Bickersteth’s paper appeared, with the exception that in my experiment the artificial respiration was performed with air containing ten per cent. of vapour, and in Mr. Bickersteth’s the vapour was an unknown quantity. In both experiments, the heart of the animal was exposed. In that which I performed, three or four inflations of the lungs almost paralyzed the heart; and nine or ten inflations, which did not occupy half a minute, had the effect of paralyzing that organ irrecoverably. In Mr. Bickersteth’s experiment, the effect of the artificial respiration was as follows:—“After continuing it for seven minutes, the diaphragm, hitherto unaffected, began to move very irregularly and imperfectly; then its movements became slow and hardly perceptible; and, at the expiration of eleven minutes, they had ceased altogether. During all this time the heart’s action remained strong and regular, but now it got weaker and more rapid, and, in four minutes from the time the diaphragm had ceased acting, had become so feeble (still quite regular) that I feared every moment it would stop.” Mr. Bickersteth says he performed artificial respiration with air saturated with chloroform; but saturated or not, the vapour certainly did not exceed six per cent., and most likely was only between four and five, if the artificial resembled the natural respiration in quantity and frequency. The vapour which can be breathed for seven minutes without causing serious symptoms, and for eleven minutes without arresting the breathing, is of course incapable of stopping the action of the heart by its direct effect. It is scarcely so strong as that which one administers every day to patients with impunity. The vapour which is so diluted as to require to be added by small increments during one hundred and fifty inspirations, before the brain is even narcotized, cannot act directly on the heart, an organ which can bear a much larger amount of chloroform. Mr. Bickersteth fell into the error into which the Committee of the Society of Emulation of Paris afterwards fell, and argued from the rule to the exception. What he witnessed was the mode of death which would occur, if vapour of chloroform of the strength which can be safely inhaled, were deliberately continued till the death of the patient. But an accident from chloroform is an exception, and the mode of dying is as much an exception as the death itself, if the inquiry is extended to what this