fall on its surface, at the middle of the card, a thick aqueous solution of an alcoholic extract of nux vomica, a substance the action of which on dogs is very energetic: I took care that no portion of the poison should touch any other part than the vein and the card, and that the course of the blood was free in the interior of the vessel. Before the lapse of the fourth minute, the effects which I expected were manifested, at first but feebly, but afterwards with such severity that insufflation of the lungs was necessary for the preservation of the life of

the animal.”

Similar results were obtained, on repeating the experiment on an adult dog. It remained to try it on an artery. This was effected on the carotid arteries of two large rabbits. The effects were developed in both animals, and one of them died. "To assure myself," Dr. Magendie says, "that the poison had really traversed the parietes of the artery, and that it had not been absorbed by the small veins which might have evaded my dissection, I carefully detached the vessel which had been the subject of the experiment; I divided it throughout its length; and I persuaded the persons who assisted me to taste the little blood which had remained adherent to its interior surface: they all recognized, as well as myself, the extreme bitterness of the extract of nux vomica,"

In order to ascertain whether the minute vessels also permitted fluids to traverse their parietes, Dr. Magendie made the following experiment:-"I took," he says, "the heart of a dog who had died on the preceding evening; I injected into one of its coronary arteries, water of 30 centig. (85° Fahren.) This water readily returned by the coronary vein into the right auricle, whence it flowed into a vessel. I poured into the pericardium half an ounce of water slightly acidulated. At first the injected water showed no sign of acidity; but, on the lapse of five or six minutes, it presented unequivocal evidence of the possession of that quality." Thus, the fact in question appeared to be proved in respect to dead minute vessels: in regard to living vessels of this class, Dr. Magendie says, "it was not necessary to have recourse to new inquiries, nor to sacrifice more animals. The experiments which I mentioned in my memoir on the Organs of Absorption in the Mam. malia, left no doubt on this point, according to the judgment of the Academy."

With respect to the permeability of membranes by certain fluids during life, (evidence of which occurring after death is found in the colouring of the parts adjacent to the gall-bladder with bile,) Dr. Magendie observes, that he has often seen membranes penetrated and coloured by substances placed in contact with them: for example, if a certain quantity of ink is put into the cavity of the pleura of a young dog, the lapse of an hour is only necessary in order that the pleura, the pericardium, the intercostal muscles, and the surface of the heart itself, may be rendered black.

The principal inference drawn from the above-mentioned facts by Dr. Magendie is this: the capillary attraction of the parietes of the small vessels appears to be the cause, or, more exactly, one of the causes, of the absorption called venous;" whilst he takes care to add,

that "this conclusion does not touch' in any respect the absorption which is effected in the small intestine on the chyle, by the chyliferous vessels, and still less the absorbent property of the lymphatics; though the experiments I have just described seem to indicate, that if, in the greater number of instances, these vessels do not absorb, this depends not on their parieties, which have properties similar to those of the veins, but to the want of a continuous current in their interior." Dr. Magendie has also made some experiments with the view of settling the questions of the irritability of the arteries, and whether any contraction on their part assists in effecting the circulation of the blood. He says, he has submitted both the large and small arteries to "the action of sharp instruments, caustics, and galvanism, and has never perceived any thing resembling a phenomenon of irritability." The small as well as the large arteries "have remained perfectly motionless under the action of the scalpel, caustics, and the galvanic current." He then says," Irritability, therefore, does not exist either in the large or in the small arteries." This experimentalist, it may be proper to remark, calls the notions of VIUESSENS, BOERHAAVE, FOUQUET, BORDEU, and BICHAT (whose opinions, on this point, are those of JOHN HUNTER,)" jeux d'esprit," and preaches, in every page of his writings, against the belief of any thing of which we have not sensible evidence; and yet he himself draws a positive inference from a few negative arguments founded on the results, perhaps but ill-observed, of some insufficient and vague experiments. He does not seem aware that he, in drawing the above inference, has hypothesized as grossly as any of those whom he would censure with so much violence. Such conduct would not have here received any serious attention, were it not that Dr. Magendie has wished to make himself very conspicuous, and has expressed some high pretensions to the improvement of physiology.t

Though the arteries do not possess irritability, Dr. Magendie docs not thence infer that they have no action on the blood on the contrary, he thinks that the arteries act on the blood by their "elasticity," or by the "disposition they have to restrict, and even to obliterate, themselves." The existence of this property in the arteries is, he thinks, showed by the following observations. He laid bare the crural artery and vein of a dog, and put a ligature round the whole of the limb excepting these two vessels; he then tied the crural vein, and opened it below the ligature: the blood sprang from it in a continuous jet, of considerable volume. He then compressed the artery: the jet from the vein continued for a few instants, but it diminished as the artery became devoid of blood, and ceased entirely when it was com pletely empty although the vein was "gorged" throughout its whole. length, blood no longer escaped from the opening in it. The com.

Journal de Physiologie Expérimentale, No. II.

He has published a series of axioms of the qualities requisite in a person who cultivates physiology, in which, it is very curious, no mention is made of that which is most essential, and without which, indeed, "observation and experi ments" are useless,-that this person should know what is right reasoning, and what is not.

pression of the artery was removed at this instant; the blood entered the vessel, and the jet of blood from the vein was immediately renewed. Similar results occurred in the several repetitions of this experiment that were instituted. Wishing to show the supposed fact in question in another manner, he introduced the extremity of a syringe filled with warm water into the crural artery, and gently propelled the piston: the blood in the vein instantly escaped, at first alone, and then mingled with water, in a jet which was more or less considerable according as more or less force was exerted on the piston of the syringe.

The admission of the influence of this elasticity on the circulation, implies a belief that the arteries are dilated by the impulse of the blood coming from the heart: this dilatation, which has been denied, as a sensible phenomenon, by one of our most careful observers, has been very apparent to Dr. Magendie, in the thoracic aorta and carotid artery of a horse. Dr. Magendie, deviating again from his own precepts, says, "not only does this dilatation exit, but it is impossible that it should not take place; for, the ventricle driving suddenly a new quantity of blood into the arteries already perfectly full, produces pressure in every direction; one of the effects of which must be the extension of the elastic parietes of the arteries."

Some observations made by Dr. Magendie from the results of injection of oil in the mesenteric veins of dogs, appear, by the phenomena developed in the liver, to support, in some degree, the opinions of Professors Tiedmann and Gmelin, of the assimilative functions of this organ. Dr. Magendie, in some experiments, in which his object was to change the nature of the blood, had injected oil into the veins, thinking that this innocent substance could circulate with the blood without inconvenience:" but this was not the case; "the animal subjected to the experiment died a few instants after the injection of an ounce of olive.oil into the jugular vein."—" On examining the organs after death, I saw (Dr. Magendie says,) that the olive oil had plugged the extreme ramifications of the pulmonary artery, and that it had thus caused the circulation and respiration to cease, by preventing the arrival of the blood at the left side of the heart by the pulmonary veins. The oil had acted, then, as an inert, impalpable powder, suspended in water, which instantly produces death if it be injected into the jugular vein, because it obstructs the extreme divisions of the pulmonary artery." A somewhat-thick solution of gum tragacanth "produced exactly the same phenomena as the oil."

Dr. Magendie had ascertained that substances injected into one of the branches of the vena porta, acted quite differently from what they did when introduced immediately into the general venous system. A few cubic inches of air thrown suddenly into the jugular or crural vein, kill almost instantly; whilst this fluid may be introduced, in any way whatever, into the branches of the vena porta, without "inconveni ence." Dr. Magendie wished to know, then, what would be the effects of oil passed into the vena porta. Two ounces of this fluid were thrown into one of the mesenteric branches of that vein: the dog, which was the subject of the experiment, continued for several days in

a stage "approaching to death,"-lying on his side, breathing with difficulty, making no movements, "not even for the natural evacuations, which seemed to be effected involuntarily." After the lapse of four days," he began to come to himself; he took some food; and three days more were sufficient to restore him to health." The injection was repeated after the lapse of eight days, with, however, three ounces of oil. "The same symptoms (Dr. Magendie says,) showed themselves, and the animal died in the night. I opened him the next morning. The vessels contained here and there some traces of oil; but the liver especially attracted my attention: this viscus was much larger than ordinarily; it was of a pinkish pale-yellow colour; some small irregular fissures were apparent on its surface, that did not appear to be of recent origin; its colour interiorly was similar to that of its surface: the organ, in a word, showed the closest analogy with the fat liver of birds.

"This last circumstance has appeared to me to be very curious, Indeed, the fat livers are produced by forcing the animals to digest a large quantity of aliments containing but little azote. These animals having no chylous system, (as I have shown in a memoir expressly on this subject,) all that is absorbed by the intestinal surface passes immediately to the liver; whilst in the mammalia, the drinks, and probably a small part of the chyle, alone pass through the liver; the rest of the chyle passing through the thoracic duct."

Dr. GASPARD, of Saint-Etienne, has published an account of some experiments made on the injection of mercury, in the metallic state, into the blood-vessels of dogs and some other animals. When inserted by the jugular vein, the animal soon evinces signs of difficulty of respiration, and obstruction to the circulation of the blood in the lungs; and, after the death of the animal, the metal is found entirely arrested in the capillary vessels of the lungs, where it has produced inflammation, and sometimes suppuration. Half an ounce of mercury, "with some water," was injected into the left carotid artery of a sheep. The animal died at the end of fifty hours afterwards. On examining the body, the left eye was found to be in a state of suppuration, and contained mercury; the thyroid, pharingean, lingual, auricular, labial, nasal, and cerebral, arteries of the left side were "admirably injected with the metal; but their capillary terminations did not contain a particle of it. All the organs on this side were tumid and very much inflamed; and it was very curious," the experimentalist says, 66 to see the half of the thyroid gland, the tongue, the face, the lips, &c. thus red and inflamed as far as the median line, the point where the arteries terminated, whilst the other half was pale and healthy. The left hemisphere of the brain, especially the plexus choroides, was also a little inflamed. I could not discover a globule of mercury in any other organ." An injection of the metal into one of the mesenteric veins of a dog, was then made: on the lapse of fifty hours, the animal was apparently dying, and was killed. The mercury was entirely arrested in the liver.

Several authors, worthy of implicit credit, have mentioned having found considerable quantities of fluid mercury in different parts of the

body, after this mineral had been used, in frictions, for the cure of syphilis. Dr. Gaspard thinks that it has been "infinitely" divided in the preparation used, and that its particles have very slowly aggre. gated in organs where the circulation is most inactive.

It would appear, from some very recent experiments by Dr. RHADES,* that the symptoms of violent effects of mercury, as great salivation and the rest, may be present, in dogs at least, and the ani. mal may die at this time, and yet not a particle of mercury can be found in any part of the body after death. Dr. Rhades had dogs rubbed with mercurial ointment until such symptoms were produced; and whilst they were at their height, some within a day or two, others later, after the suspension of the frictions, the dogs were killed. The blood and all the solid parts of the body were examined with all possible attention, by the nicest chemical processes, but the results were as above stated. Prof. AUTENREITH had asserted+ that he found mer. cury under such circumstances. Considering this statement, with the observations already alluded to, ‡ of mercury being found in the humaq body, we must infer, not that mercury is not absorbed and carried into the circulation, but that, after being thus received, it is quickly evacuated by the emunctories; and that the symptoms of its action will continue for a considerable time after it has ceased to be present in the body.

The disputes respecting the power of galvanism to maintain the process of digestion, in a rabbit, after the eighth pair of nerves has been divided in the neck, seem to be finally determined by the results of an experiment (in which the efficacy of that agent was proved) performed, at the Royal Institution, by Dr. WILSON PHILIP. The nerves were divided in a rabbit soon after it had eaten copiously of parsley: galvanism was employed, in the way recommended by Dr. Philip, and the animal died at the end of seven hours. The contents of the stomach were immediately afterwards exposed, and presented appearances similar to those which would be observable in the contents of a healthy rabbit killed at the same period after having eaten of the same food. The digestive process had not, perhaps, advanced quite so far in the subject of the experiment as in a healthy rabbit; but the difference, if there was any, was not strikingly remarkable.§

In a rabbit which, for the purpose of a comparison, had been submitted to the same circumstances, with the exception of the influence of galvanism, the contents of the stomach were found to have suffered but very little alteration by digestion; their colour was but little changed, and they were comparatively dry throughout, excepting at the surface, in contact with the stomach, where a slight degree of digestion had been effected. The lungs of this rabbit were found

Published in Meckel's Deutsches Archiv für die Physiologie. Sechster band; erstes heft.

+ Reil's and Autenreith's Archiv für die Physiologie, 8 band.

See the writings of Fallopius, Fernelius, Mead, Boyle, Van Swieten, Schenk, Bonetus, Vieussens, Woolhouse, and Fourcroy.

The writer speaks from his own observation.

Very different results are stated by Mr. BROUGHTON to have ensued from