Volume 1

The collected papers of Sir W. Bowman, Bart., F.R.S / edited for the committee of the "Bowman Testimonial Fund" by J. Burdon-Sanderson and J. W. Hulke.

  • Bowman, William, Sir, 1816-1892.
Date:
1892
    xxx INDEX OF CONTENTS. III.—FROM THE ' CYCLOPAEDIA OF ANATOMY AND PHYSIOLOGY.' Mucous Membrane Muscle Muscular Motion ..
    CONTRIBUTIONS TO THE PHILOSOPHICAL TRANSACTIONS.'
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    ON THE MINUTE STRUCTURE AND MOVEMENTS OF VOLUNTARY MUSCLE. By William Bowman, Esq., Demonstrator of Anatomy in Kings College, London, and Assistant Surgeon to King's College Hospital. In a Letter addressed to Eobeet Bentley Todd, 31.D., F.R.S., Professor of General Anatomy and Physiology in King's College, London. Communicated by Professor Todd. Received June 18.—Read June 18, 1840. My dear Dr. Todd, In offering to your notice the following account of some researches into the minute structure and movements of voluntary muscle, which I commenced at your suggestion, and in the prosecution of which you have so materially aided me, I am encouraged to hope that some parts of the inquiry may not be altogether uninteresting to the Eoyal Society, to which the first discoveries in this important branch of physiology by Eobert Hooke and the illustrious Leeuwenhoek were communicated, and which also possesses, in its later Transactions, important papers on the same subject. It has long been known that voluntary muscle is susceptible of subdivision into minute threads, which being almost uniform in size, unbranched, and united by means of vascular and cellular parts into bundles of varying bulk, have generally been regarded as constituting the essential proximate anatomical element of the organ. All the best observers, since the time of Leeuwenhoek, have recognised the existence of these threads, but their form and composition have been objects of continual dispute, and in the present day we seem to be as little advanced towards the determination of their real nature as ever. The improvements which have taken place in the construction of microscopes, appear indeed to have only afforded grounds for new differences of opinion, as may be seen by the records of the last few years. In 1837 Mr. Skey, after an elaborate investigation, concluded that these threads were tubes containing a soluble gluten, round which were disposed, in longitudinal sets, still finer filaments, which in their turn were held together by circular bands or striae ; and since that period, Dr. Mandl, a microscopical observer in Paris, has described B 2
    and figured them as bundles of fibrils, held together by a spiral coil of filamentous tissue. A more common opinion is, that these threads are bundles of beaded fibrillae, whose beads being placed side by side, cause the appearance of transverse lines, a view which was first entertained by Fontana,, though his claims to it have been often overlooked. More lately Dr. Schwann and M. Lauth have advocated the same doctrine, especially the former, who has adduced additional arguments in its support. My design in the present paper is, first, to vindicate, under certain modifications, the general correctness of this opinion, and to render more exact and ample the knowledge of its details; secondly, to point out the existence and properties of new parts which, as far as I can ascertain, have not yet been described; and thirdly, to elucidate the proximate cause of voluntary motion, by describing shortly the mechanism of certain movements performed by the elementary constituents of muscles. In speaking of the threads already mentioned, it becomes necessary to attach to them a term of definite meaning. The words fibre, fibrilla, and filament, have been so much abused by indiscriminate application, that it would be confusing the subject to employ them in this sense; and though the term primitive fasciculus, adopted by Font an a and some subsequent writers, will be shown in the sequel to be liable to considerable objections, as implying a composition by smaller fibrils, which can never be said to be a correct expression of the actual condition, yet I shall prefer its use to that of a new designation. The small component fibrils, into which the primitive fasciculus may usuafly be split up, will be styled primitive fibrillar, or simply fibrillar. As even the configuration and bulk of the primitive fasciculi have not hitherto been fully ascertained, these points demand attention. Their shape may be briefly described as polygonal in all animals, though in some examples they approach very nearly to a cylindrical form. The examination may be conducted by obtaining either a longitudinal or transverse view of the parts ; but the former, without precaution, is apt to lead to error. It is usual to place the recent fasciculi, moistened with water, between glasses, previous to inspection, whereby they become swollen from absorption of the fluid, and more or less altered towards a cylindrical figure. If this mode of examination be desired, it is requisite, therefore, either nut to wet the object, or to moisten it with a fluid which is not absorbed, such as thick syrup. It will then be seen that the cross markings, called transverse strise, with which every anatomist is familiar, as visible on the fasciculus, have not uniformly a straight direction across it, but are frequently all bent at an obtuse angle, along a certain line parallel to the margin, showing a sudden change in the aspect of the surface on which the strife are seen. This appearance was not unobserved by Fontana*, who in a figure of four * Fontana, Traite sur le Venin de la Vipere, Tab. vi. Figs. 6, 7.