XI. "Electro-Physiological Researches."-Tenth Series. Part I. By Signor CARLO MATTEUCCI, Professor in the University of Pisa. Communicated by MICHAEL FARADAY, D.C.L., F.R.S. &c. Received June 12, 1856.

(Abstract.)

In the first section of this part of his Memoir, Professor Matteucci treats of the heat developed by muscles during contraction. Adverting to earlier experiments by other inquirers, in which a rise of temperature was observed to take place in the contracting muscle while the blood still continued to circulate through it, and where, consequently, it remained uncertain how far the effect might not be due to a modification of the circulation, the author describes his own experiments, by which it is shown that the muscles of frogs, after all circulation of the blood has ceased, and by the sole act of contraction, cause a rise of temperature amounting to about half a degree Centigrade.

The second section is devoted to the consideration of the electric current exhibited by muscles at rest, and experiments are adduced in illustration of the following propositions :

a. The electro-motive power of a cut muscle is independent of the size of its transverse section.

b. The electro-motive power increases with the length of the muscle.

c. The electro-motive property of the muscles of living or recently killed animals is greater in mammals and birds than in fish and amphibia. The duration of this force, which in all cases decreases most rapidly in the first moments after death, is greater in fish and amphibia than in the higher orders of animals.

d. The nerves have no direct influence on the electro-motive force of muscles. In general, all causes which exert an influence on the physical structure and chemical composition of muscles, so as to modify, in ways unknown, their irritability or contractility, act equally on their electro-motive power.

Prof. Matteucci here takes occasion to state, that he has verified the important discovery of Du Bois Reymond, of the existence of an

electric current in portions of nerve detached from the body,-a current which, like that of muscle, passes, in the galvanometer, from the surface of the nerve to the interior. He adds, that he could perceive no marked difference in the relative duration of the electromotive power of muscle and nerve.

In the third section, the author discusses anew, and with the aid of fresh experiments, the phenomenon originally named by him induced contraction, in which the nerve of a "galvanoscopic limb" of a frog, being laid on a muscle of a living or recently killed animal, is stimulated by the contraction of that muscle, so as to cause at the same moment contraction in the muscles of the galvanoscopic limb. He endeavours to show, that this phenomenon is due to an actual electric discharge, which takes place in a muscle at the moment of contraction, in an opposite direction to the ordinary current of the muscle while at rest. The deviation of the galvanometer-needle during the contraction of a muscle, which occurs in an opposite direction to that previously caused by the electric current generated by the muscle while at rest, was ascribed by M. Du Bois Reymond to the diminution or cessation of the latter current when the muscle contracts, and to the operation in such circumstances of the secondary polarity of the platinum plates of the galvanometer. Professor Matteucci, however, adduces various experiments to show, that, by certain arrangements described, he is able entirely to prevent the occurrence of secondary polarity, and that nevertheless the deviation of the needle takes place.

After adverting to the want of reliable data on which to found an explanation of the physical cause of the phenomenon in question, the author hints, that as there is no analogy between the form of the voltaic electromotor and that of the molecular electromotor, it is not impossible to conceive that the change of form which takes place in a muscle during contraction may be momentarily followed by the inversion of the muscular current in the exterior arc. He observes, that examples are not wanting, taken from certain cases of electrodynamic induction, and also of voltaic circuits, in which this inversion of the current can be obtained by a change in the form, or relative distance of different parts of the circuit; but he adds, that this is a new field of inquiry, which cannot be given up to merely hypothetical

views.

The last section of the paper is devoted to the consideration of the mechanical effects of muscular contraction; and experiments are stated with a view to compare the effective work of a muscular contraction, as determined empirically with the work calculated according to the principles of the dynamical theory of heat.

Employing the dynamometer already described in the fourth series of his researches, the author has found that the mechanical work effected by a single contraction of the gastrocnemius muscle of a frog may be expressed by 0·00001457 kilogramme-metres. Determining next the quantity of zinc required to be oxidated in the pile in order to excite a single contraction, he finds that the force developed by the muscle is enormously greater than could be accounted for on the supposition that it is produced by the conversion into muscular energy of the equivalent of electricity corresponding to the quantity of zinc oxidated. He accordingly concludes, that the electric current which excites a muscle to action does not represent the force exerted by the muscle, which is more probably to be referred to the chemical changes, such as oxidation, which take place in the muscular tissue during contraction. The consideration of this branch of the inquiry will form the subject of the second part of the Memoir.

XII. "On the Existence of Multiple Proportion in the quantities of Heat produced by the Chemical Combination of Oxygen and other bodies." By THOMAS WOODS, M.D. Communicated by Professor STOKES, Sec. R.S. Received

June 7, 1856.

(Abstract.)

This paper is, in substance, the same as a former paper, bearing a similar title, read before the Royal Society on the 10th January 1856, but contains a more detailed account of the mode of performing the experiments. A repetition of the experiments mentioned in the former paper has led to very nearly the same numerical results, except in the case of molybdenum, which is found to give 4.8 thermal units by combining with oxygen, instead of 3.38, the number formerly given.

XIII. "Researches into the nature of the Involuntary Muscular Fibre." By GEORGE VINER ELLIS, Esq., Professor of Anatomy in University College, London. Communicated by Dr. SHARPEY, Sec. R.S. Received June 11, 1856.

(Abstract.)

Having been unable to confirm the statements of Professor Kölliker respecting the cell-structure of the involuntary muscular fibre, the author was induced to undertake a series of researches into the nature of that tissue, by which he has been led to entertain views as to its structure in vertebrate animals, but more especially in man, which are at variance with those now generally received. The present communication contains the results of these inquiries, which tend to show that the voluntary and involuntary muscles resemble each other very closely in the arrangement and constitution of their fibres.

After adverting to the present state of opinion on the subject, the author gives an account of his own observations, and treats successively of the interweaving of the fibres, their size, form, and ultimate structure; their mode of attachment at their extremities, their length, and the corpuscles connected with them. He devotes a section also to the question of the periodic formation and destruction of muscular fibres in the uterus, in its different conditions; and while he is led by his own investigations to recognize an enlargement in size of the individual fibres of that organ during pregnancy, followed by subsequent diminution, he is unable to confirm the doctrine of new formation. Moreover, he finds that during pregnancy a considerable amount of granular matter, with round or oval granular-cells, is deposited among the fibres. He adduces reasons for believing that this substance cannot be regarded as a blastema, nor its imbedded cells as formative cells, for the production of new fibres; and he is disposed to ascribe the enlargement of the uterus in pregnancy principally to the enlargement of the muscular fibres, and the addition of this new deposit.

The following is a summary of the conclusions which the author has arrived at on the main subject of his inquiry

:

In both kinds of muscles, voluntary and involuntary, there is an interweaving of the fibres with the formation of meshes.

The fibres in both kinds are long, slender, rounded cords of uniform width, except at the ends, where they are fixed by tendinous tissue; and in both, the size of the fibres in the same bundle varies greatly.

In neither voluntary nor involuntary muscle is the fibre of the nature of a cell, but in both is composed of minute threads or fibrils. Its surface-appearance in both kinds of muscle allows of the supposition that in both it is constructed in a similar way, namely, of small particles or sarcous elements," and that a difference in the arrangement of these elements gives a dotted appearance to the involuntary and a transverse striation to the voluntary fibres.

The length of the fibres varies in both cases with the organ or part examined, and the connexion with tendon always takes place after the same manner, whether the fibre is dotted or striated.

On the addition of acetic acid, fusiform or rod-shaped corpuscles make their appearance in all muscular tissue; these bodies, which appear to belong to the sheath of the fibre, approach nearest in their characters to the corpuscles belonging to the yellow or elastic fibres which pervade various other tissues; and, from the apparent identity in nature of these corpuscles in the different textures in which they are found, and especially in voluntary as compared with involuntary muscle, it is scarcely conceivable that in the latter case exclusively they should be the nuclei of oblong cells constituting the proper muscular tissue.

The paper concludes with a statement of the mode of procedure which the author has found most suitable for examining the tissue which forms the subject of his inquiry.