water, so as to coagulate the albumen; it is then well adapted for these experiments. Thick paper of a very compact texture would probably do without this preparation; but I cannot state this positively, not having tried it.

"I think that by the above experiment I have demonstrated the existence of a power not before noticed in the voltaic current, namely, that of conveying fluids through minute pores not otherwise pervious to them, and overcoming the force of gravity.

"Is not this electro-filtration, jointly with electro-chemical action, in constant operation in the minute vessels and pores of the animal system?

"I wish that some person well versed in the sciences of anatomy, chemistry, and electricity, would answer this question. I am not qualified to attempt its solution, being a stranger to the first-mentioned science, and possessing but a moderate knowledge of the other two; and it appears to me that only a proficient in all should venture to propose any new physiological opinions, but I cannot help thinking that an affirmative answer to the above question is capable of a good defence.

To those who may be inclined to repeat the preceding experiment, it may be useful to mention that, by letting fall from a dropping tube a little sulphuric acid into the cells of the battery occasionally, its action is prolonged, without the trouble of renewing the liquid in the cells, or the inconvenience of disturbing the whole arrangement, the partial action of this dense acid on the plates is prevented by stirring the liquid afterwards with a little stick."-P. 76.

After this réclamation we proceed with our notice of the Leçons. The simple fundamental fact relative to endosmose is thus stated by Matteucci. "Here is a glass tube, whose lower extremity is expanded into the form of a funnel, and is closed by a piece of bladder. This instrument is called an endosmometer. If we pour into it an aqueous solution of either gum or sugar and then plunge the closed extremity into water, we shall observe that, notwithstanding the excess of pressure of the column of liquid, the water continually passes into the tube by filtration through the membrane. The liquid within the tube thus becomes elevated to a certain extent and may even flow over at the upper extremity: at the same time, however, a certain quantity of mucilaginous or saccharine liquid escapes from the tube through the bladder and mixes with the water; but the quantity is necessarily less than that of the water which passed through the membrane from without inwards. Dutrochet has applied the term endosmose to the first of these phenomena (that is to the passage of the fluid from without inwards), and that of exosmose to the passage of the fluid from within outwards.

"Membranes produce endosmose until they begin to putrefy, when the phenomenon ceases, and the liquid, which had been elevated in the tube, falls and filters through the membrane."

The phenomena of endosmose are not confined to membranes, nor even to organized substances. Plates of slate or of baked clay produce, though in a weaker degree, the same phenomena.

The nature of the liquid has a considerable influence on the process. "It is a curious fact," says Matteucci, "that the slightest trace of sulphuretted hydrogen modifies the production of this phenomenon, even with the most active liquids: whereas other acids, as the hydrochloric and nitric, have no effect on it.

"When compared with water, all animal liquids produce endosmose with much energy, except those contained in the large intestine. These probably become exceptions on account of the sulphuretted hydrogen which they contain."

Matteucci then briefly notices Dutrochet's experiments on the velocity of endosmose with different fluids, and mentions the curious fact, that cer

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Agency of Endosmose in Cell-life.

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tain acids, when mixed with water, change the direction of the current. After some remarks on the force of the endosmotic current and the insufficiency of theory to account for the phenomenon, Matteucci observes—

"What we have now stated is sufficient to convince you that this phenomenon is perhaps the most important of physical facts, with respect to its applications to the functions of living bodies.

Microscopic observation has now put beyond a doubt that in all tissues, vegetable or animal, and in those liquids which are produced by the alteration of organized and living beings, there is constantly found, at a certain epoch of their formation, microscopic corpuscles, which have a peculiar and characteristic form, and are called elementary or primitive cells. These bodies consist of an excessively fine membrane, have a spherical form, and enclose a liquid. On the inner side of the membrane is a small organized body, called the nucleus or cytoblast. The cells float at first in a liquid which Schwann has named cytoblastema, and ultimately become included in, and almost confounded with it, when this liquid becomes more or less dense. In different tissues, the elementary cells are more or less closely approximated to each other; the cytoblastema, or intercellular substance, is invariably the bond of union between the cells. Hereafter we may perhaps return to this important subject, which we have now only glanced at, in order to render more evident the importance of the phenomenon of endosmose. The life of the elementary cells certainly forms the part which is the most essential to the development and preservation of the tissues of living bodies; and, since these cells are found under conditions favourable to endosmose, we can assign no reason why it should not take place. A vessel filled with a liquid, and placed in the midst of another liquid, may act on the outer one, receive the surrounding liquor, and reject the one it had previously contained, by operating in a manner analogous to endosmose.

"We must, however, confess that hitherto very few investigations have been undertaken with the view of making such applications of the phenomenon of endosmose to physiology as it appears to be susceptible of. To do this it was necessary to vary the liquids between which endosmose takes place, and to select the membranes, so that we might always keep as close as possible to the conditions under which the analogies between the phenomenon and those which take place in the interior of living bodies have been observed. This I undertook to effect, in conjunction with Professor Cima; and I shall now bring before you the result of our researches. The membranes which we submitted to experiment may be divided into three classes: the first includes the skin of the frog, the torpedo and the eel; the second, the stomach of the lamb, the cat and the dog, and the gizzard of the fowl; and the third, the bladder of the ox and of the pig.'

Matteucci then proceeds to explain the apparatus employed, and the conditions under which the experiments were made, to determine the influence which the membranes of these three classes exercise on endosmose.

One of the most remarkable facts discovered by MM. Matteucci and Cima is the marked influence exercised on the phenomenon of endosmose by the position of the membrane interposed between the two liquids. Thus, in the case of the fresh mucous membrane of the bladder of the ox, deprived of the muscular coat, this influence was very manifest.

"When this membrane was employed, and a solution of sugar introduced into the interior of the two endosmometers, the height at which the liquids arrived in the tubes was, when the internal surface of the membrane was in contact with the saccharine liquid, 80 and even 113 millimetres in the usual space of two hours; but it was only 63 or 72 millimetres when the position of the membrane was reversed. The current of endosmose then is promoted in this instance from the external to the

internal surface of the membrane. The contrary effect is obtained with the solution of gum arabic. The elevation is 18 and sometimes only 7 millimetres, when the internal surface is turned towards the interior of the instrument, when it contains the gum solution; whereas, when the membrane is arranged the reverse way, the elevation is 52 millimetres, or, in some cases, 20 millimetres."

The general conclusions drawn from the various experiments made by MM. Matteucci and Cima on this subject are thus stated by Matteucci:

"1st. The membrane interposed between the two liquids, in the phenomenon of endosmose, has a very active share in the intensity of the endosmometric currents, as well as in its direction.

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2nd. There is in general, for each membrane, a certain position in which endosmose is the most intense; and the cases are very rare in which, with fresh membrane, endosmose takes place equally, whatever be the position of the membrane to the two liquids.

"3rd. The direction which is most favourable to endosmose through skins is, usually, from the internal surface to the external, with the exception of the skin of the frog, in which endosmose, between water and alcohol, is promoted from the external to the internal surface.

"4thly. The direction favourable to endosmose through stomachs and bladders varies much more than with skins, according to the different liquids.

"5thly. The phenomenon of endosmose is closely allied to the physiological condition of the membranes.

"6thly. With membranes dried or altered by putrefaction, either we do not observe the usual difference belonging to the position of their surfaces, or endosmose no longer takes place."

The following extract forms the conclusion of the third lecture of Matteucci's very interesting work:

"It is by endosmose that physiologists now explain the nutrition of the ovules in the oviducts of mammalia, and how the sacs which contain the sperm of the cephalopodous molluscs open immediately they are brought into contact with water.

"A cell is the elementary organ of all animal and vegetable tissues, and cell-life involves an act of endosmose: this shows how much the phenomenon of endosmose is still in want of being more completely studied, in order that we may be enabled to make of it all the applications of which it is susceptible. I cannot conclude this lecture without referring to the recent experiments of Poiseuille, made with the view of explaining by endosmose the purgative action of certain substances. He found that there was endosmose through animal tissues from the serum to Seidlitz water, and to the solutions of sulphate of soda and common salt. Now this is precisely what happens when we use these medicines internally. The rejected excrements contain an abundant and unusual quantity of albumen: in this case we must admit that endosmose takes place through the capillary vessels of the intestine, from the serum of the blood to the saline solution introduced into the alimentary canal.

"But, to remove all doubt of the propriety of Poiseuille's applications of this fact, it was necessary to demonstrate that endosmose takes place when one of the liquids is in motion, and is continually renewed.

"This has been recently done by Dr. Bacchetti, who has shown that the rapidity of endosmose is considerably augmented when one of the liquids was continually renewed. This result, moreover, is in accordance with the principles of the theory of endosinose: the exchange of liquids constantly effected through the membrane, leads to the suspension of the action of endosmose; or, in other words, the conditions for the production of the phenomenon are so much the

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The Muscular Electric Current.

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better preserved, as the liquids remain longer without mixing. Poiseuille has also shown that endosmose ceases to take place in a membrane after a certain time of action, but that we may restore to the membrane this property by submitting it to the action of other liquids. The most remarkable fact discovered by Poiseuille is that of the influence exercised by hydrochlorate of morphia. This body added to saline solutions weakens very considerably the endosmose from the serum to the solution; and ultimately changes the direction of the current. This fact has been confirmed by Dr. Bacchetti. How can we make an entire abstraction of this fact in the explanation of the action of morphia and the preparations of opium in diarrhoea, and of the constipation which they produce?"

The Muscular Current.-In the paper on the muscular current, presented by Matteucci to the Royal Society and printed in their Transactions, the results obtained from his different experiments are thus summed up.

"In the first place, the intensity and duration of the muscular current are independent of the nature of the gas which envelops the muscular pile. Secondly, this current, as I have already shown from the commencement of my researches, is altogether independent of the cerebro-spinal nervous system, and the circumstances which exercise a marked influence upon its intensity are respiration and the sanguineous circulation. Thirdly, those poisons which seem to act directly upon the nervous system, have no influence upon the muscular current; among these I would mention hydrocyanic acid, morphine and strychnine. Fourthly, sulphuretted hydrogen has a marked influence in diminishing the intensity of the muscular current. Fifthly, the intensity of the muscular current varies according to the temperature in which the frogs have lived a certain time; it is needless to observe that this result is not discoverable except in those animals which, like the frog, necessarily take their temperature from that of the medium in which they live. Sixthly, the intensity of the muscular current increases in proportion to the rank the animals occupy in the scale of beings, while the duration of this current, after the death of the animal, is in an exactly inverse ratio.

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Comparing these conclusions with those generally admitted by physiologists, and drawn from a great number of experiments on the vital properties of muscles, it is impossible not to perceive that the property of the muscles, immediately connected with the muscular current, is that which Haller calls irritability, and which at the present day, I believe physiologists designate by the name of organic contractility, or simply contractility."

Our readers will not fail to perceive that the conclusions drawn by Matteucci from his experiments are opposed to the views of Dr. Marshall Hall. The Italian Professor regards the irritability of muscular fibre as inherent; whereas Dr. Hall considers it as derived from what he calls the true spinal system.

"With regard to the manner of representing the origin of the muscular current," says Matteucci, "I find, in my present experiments, a confirmation of the opinion I set forth in my preceding ones. The chemical action which goes on in the nutrition of the muscle, principally that which takes place in the contact of the arterial blood with the muscular fibre, is in all probability the source of this electricity in the muscles."

Some of the recent investigations of Liebig have reference to the origin of the muscular current. The celebrated Giessen Professor has at last succeeded in demonstrating the existence of free lactic and phosphoric acids in the muscles of animals. He thinks that his results "explain the quick re-action of the muscles," and he adds that, now that "we know

that there exists, in so large a portion of the body of animals, an acid liquor, which is only separated from an alkaline fluid (the blood and the lymph) by very thin membranes, we may, I think, explain several electrical phenomena observed by Matteucei and other physiologists upon the bodies of dead (and living) animals." (See Chemical Gazette, Feb. 1, and Feb. 15, 1847; also Comptes Rendus, Jan. 18th, 1847.)

The Proper Current of the Frog.-In our review of Matteucci's Traité des Phenomenes Electro-physiologiques (Medico-Chirurgical Review for April, 1845), we protested against Matteucci's assumption that the frog had any peculiar electric current; and we did so because it appeared to us that the assumption was in opposition to every thing then known respecting the organization and physiological relations of animals; and we observed that we could not "for a moment admit the probability of the frog possessing a peculiar electric current, unendowed as this animal is with any peculiar organs or electric apparatus." And we further stated our confident belief that, "whatever currents may be detected in the frog, the same will be found to exist, in some degree of intensity, in other animals.” The accuracy of our view is now fully established by the more recent investigations of Matteucci himself, detailed in his second Memoir, subsequently published in the Philosophical Transactions.

From the additional experiments, referred to in the Memoir just quoted, made with the view of clearing up certain points which had been left in an unsettled state, in the Traite, Matteucci concludes,

"That the proper and the muscular current are in general subjected to the same laws, and that both these currents vary in the same sense, under the same circumstances."

Feeling the importance of solving the question why the proper current should belong exclusively to the frog, Matteucci next directed his attention to this point, and arrived at the following

"Generalization of the fact of the proper current of the frog; the current is directed within the muscle from the tendon to the superficies.

"It remained for me to extend this fact to its operation upon the muscles of warm-blooded animals, and the experiments accorded in such a manner as to leave no possible doubt."

His experiments were made on fowls, pigeons, rabbits, and dogs; and their results were such as to establish the correctness of the position we took up in the review before quoted; and we therefore claim for ourselves the credit, small though it be, of having denied the speciality of the proper current in the frog, and of having asserted our belief of its universality in animals. In his Leçons, Matteucci thus clearly states the conclusions at which he has recently arrived.

Recently, by studying more attentively the proper current, I have satisfied myself that it is a phenomenon which appertains to all animals. Here is the enunciation of the fact; in every muscle endowed with life in which the tendinous extremities are not equally disposed, there exists a current directed from the tendon to the muscle, in the interior of the muscle. All animals have muscles in which one tendinous extremity is narrower than the other; which at one part forms a kind of cord, and at the other becomes broader and ribbon-like. In the