With respect to the administering of prussic acid, to lower the pulse in consumption, we cannot TOO STRONGLY reprobate this mistaken practice. Do physicians, when prescribing this poison, ever reflect that this elevation of the pulse, which they employ themselves so sedulously to lower, is an effort of nature to supply more oxygen to the system by an increased action of the lungs, and that the more the lungs are injured by disease, the greater is this compensating effort of nature: just as a blacksmith must work a small or defective bellows more rapidly than a large one, to keep his fire going. If this be the case, the destructive effects of prussic acid will at once be evident, since by it all the powers of the system become reduced, and nature’s efforts at self-relief most mischievously obstructed. The feverish action of the pulse is, in itself, of no moment; it is only as a symptom of derangement in the system that it becomes alarming; it is nature telling us that something is wrong by the very action which she is establishing to cure it. What then must be thought of a practice which silences the tell-tale pulse, stops the voice of nature, and checks her curative efforts, without attempting to cure the disorder; doing immense mischief, whilst it effects no good? The fact is, the only reduction of the pulse which is worth a farthing, is that which follows naturally from removing the cause of its elevation, viz., a want of oxygen in the system. That the supplying of this want has the effect of lowering the consumptive pulse, without the assistance of prussic acid, is abundantly proved by the rapid fall of the pulse produced by the Turkish bath,—a result most satisfactory to the physiologist, as evidencing the soundness of the theory which prescribes it as a remedy. Having referred to the erroneous practice of swathing consumptive patients in flannel, it may not be out of place here to make a few observations on the origin of caloric in the animal system, and the office of clothing in relation to it.