tion at all, no symptom whatever has followed the injection of half a drachm of kreosote mixed with water. When double that quantity has been injected pure, death has immediately ensued, apparently occasioned by the obstruction to the pulmonary circulation, the lungs having been found black and gorged with blood, which seemed composed of minute granules mixed with a fluid of inky blackness.

In the present state of animal chemistry, and in reasoning from so small a number of experiments, any explanation of the phænomena here detailed must be held to be conjectural. But such is in fact one great object of the Meeting. It would appear in the first place that arsenic injected into the veins exerts an influence primarily on the small intestines, that there at least its effect as an irritant begins; and as far as these experiments go it would seem that the upper part of the duodenum was the first to exhibit traces of its action. In the first experiment the large intestines were absolutely free from any organic change, and the stomach but slightly participated. When a longer period had elapsed, other portions of the gastro-intestinal mucous membrane have become inflamed, and other and remote parts have been implicated. Such a series of effects is seen in cases of poisoning by arsenic. In these the epigastrium is first referred to as the seat of derangement; then the whole alimentary canal; next the skin is the seat of an efflorescence, or rash, the urinary organs often participating at the same time. After a longer or shorter interval a crop of pustules will appear; later yet the nervous system is affected; paralysis comes on. Whether the bones would eventually become affected, as is the case with the cattle in the neighbourhood of manufactories where arsenical exhalations are generated, can only be inferred. In animals thus situated the joints become inflamed, anchyloses take place, and the bones enlarge and eventually become carious. The more minute series of vessels through which the fluids be required to pass previous to entering into these various structures, as well as a diminished susceptibility in them, and the necessity consequently for a repetition of the stimuli, may perhaps offer some explanation of these progressive affections. That the vascularity excited by arsenic taken into the stomach will doubtless be allowed to result from some chemical effect. Inflammation would not be set up by the application of a merely inert powder to a mucous surface from simple contact. cravings of hunger of certain Indians are appeased by devouring clay without exciting inflammation. Nor can the angular shape of the minute crystals be, as was formerly conjectured, the cause of the excitement of inflammation, for we know that large quan

may

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tities of pounded glass may be swallowed with impunity. That the inflammation produced by arsenic when circulated in the veins is also a chemical effect will no more be doubted than the other, as the author conjectures; for we know that many substances if soluble in the blood may be injected even in large quantities into the veins. Of this we have instances in the experiments of Orfila with the resin of jalap, and other substances. The operations then we may infer to be chemical, and inflammation to be excited in the part peculiarly susceptible of the action of the poison either because the chemical changes may take place in the part, or because the part itself may by idiosyncracy be disposed to resent that particular stimulus. Whether or not the system be chiefly on its guard against the introduction of such substances as tend to increase the disposition of the blood to coagulate may be matter of future consideration. Certain it is that metallic oxides and alcohol appear especially to excite the inflammatory condition. Equally certain it is that the elimination of the albuminous principles in the various forms of gelatine, albumen, and fibrine must be the means of the growth of natural tissues and the cause of the formation of many new structures. Albumen, it is well known, is precipitated by metallic salts, decomposition taking place, and a compound resulting, a combination of the oxide with the albumen. This compound, it is true, is again soluble in a liquid containing albumen in excess; a provision by which the formation of solid masses, which we saw in the blood of the dog poisoned by kreosote, would be prevented, and the fatal result which might otherwise ensue be obviated. But whether these chemical changes do actually occur, or whether any power of the system to prevent such an occurrence be called into play, an increased tendency to coagulation must be presumed to exist; the circulating fluids must have become more stimulating; and the disposition to a change of structure will have increased. Whether this may be the simple explanation of such albuminous deposits as are seen in the kidneys and inner coats of the arteries, especially in drunkards or in those addicted to spirit-drinking, is here advanced as appropriate matter for discussion. How far the agency of galvanism in the case of the oxides may operate in promoting coagulation may perhaps be more readily conjectured than shown. But when the coagulation of albumen is under consideration, it becomes impossible to avoid calling to mind the extraordinary facility with which that consolidation is produced by the electric fluid. And it will be enough to observe, that in all chemical changes, both of union and decomposition, this agent is in operation. What the

changes are which take place it would certainly be important to ascertain, that such is the fact, however an example or two may be cited to show. When mercury is extracted from the skin, deposited from the urine, or found in the bones of those who have been under a mercurial course, it is met with in the pure metallic form, although exhibited in that of a chloride; and iodine taken pure, and having passed through the system, is discovered in the form of iodide or hydriodate.

Speculations, it was observed, of this sort might be almost interminable. Bounds must therefore be set to such conjectures. Still the state of the blood in cases of poisoning is peculiar both in cases where the nervous energy has been highly excited, or when on the contrary it has been suddenly and greatly exhausted; where inflammation has been set up locally, or where a general inflammatory diathesis alone has been provoked. True it is indeed, and no less curious than true, that blood in the inflammatory state is less disposed to coagulate, or rather that coagulation takes place more slowly in blood drawn during inflammation than that taken from the vessels in its natural state. The author expressed the submission with which he laid these remarks before the Meeting, which, he observed, related only to those substances unquestionably taken into the circulation, and expressed his determination to dedicate his time and thoughts to the further elucidation of the ideas scattered through them, which he hoped to advance, and render more perfect before the next meeting of the Association.

Report on the Motions and Sounds of the Heart. By the DUBLIN SUB-COMMITTEE of the Medical Section.

THE Committee having met together several times, and having considered different opinions hitherto advanced on the subject of the Motions and Sounds of the Heart,' proceeded to institute a series of experiments. The subjects chosen for experiment were calves, in which animals the heart is sufficiently large to admit of the motions and sounds being accurately observed; and their early age is favourable to a prolongation of the experiment, as it has been ascertained that the vitality of the different organs is more enduring, and less influenced by injuries to the individual, in animals at a very early age than in those of maturer growth.

The animals were prepared for experiment in the following manner: a tube, connected with a pair of bellows, was introduced into the trachea, and secured there, and the sensibility of the creature having been destroyed by a blow on the head, artificial respiration was established, by means of which the heart was enabled to continue its pulsations for a period varying in different subjects from one hour to two. The Committee had been unable to procure some of the Woorara poison, which has been used in similar experiments in London; and they found that the employment of prussic acid, in a quantity sufficient to suspend the sensibility of the animal, destroyed, in a few minutes, the power of motion in the heart.

§ 1. Experiments on the Motions of the Heart.

Exp. 1. A calf, two days old, having been secured on its back, and prepared as above described, the sternum, and a portion of the ribs on both sides were removed, when the heart was seen beating strongly, at the rate of 80 beats in the minute. Whije still inclosed in the pericardium, the heart was observed to have a slight libratory motion on its longitudinal axis, which motion, it may here be remarked, may assist in explaining the phænomenon of 'frottement,' observed in disease. On cutting open the pericardium and turning it aside, both the auricular appendices were seen to project with a rapid motion upwards, or towards the place of the sternum, and immediately afterwards to recede. When coming upwards, they were swollen and soft to