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
Catalogue details

Licence: Public Domain Mark

Credit: 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. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    Of the Striped Fibres. The length, of these is usually about that of the muscle to which they belong, but occasionally they are interrupted by tendinous intersections, as in the rectus abdominis and semitendinosus; and it is very common for them to fall short of the length of the whole organ, in consequence of an oblique disposition, as seen in penniform muscles. In the sartorius they often exceed two feet in length, while in the stapedius they are not two lines. They vary in diameter from -g^th to T^o_otn °f an incn> being largest in Crustacea, fish, and reptiles, where their irritability is enduring ; and smallest in birds, where it is most evanescent. The individual fibres, however, vary considerably in thickness in the members of the several tribes, and even in the same animal and muscle. Their average width in man is about -^oth of an inch. They are not cylindrical, but flattened more or less, by being closely packed together. This may be ascertained in the recent state, or still better by a transverse section of a dried muscle. Small interspaces are left, however, for the passage of the Transverse sections of striped muscle that had been injected and dried, magnified 70 diameters :— A, From the Frog. B, From the Dog. b, b, Section of elementary fibres, showing their angular form and various size, a, a, Sec- tions of the injected capillaries, showing the position they occupy among the fibres, a, Transverse branch between two longitudinal capillaries. These figures show the greater vascularity of the muscle, with the narrower elementary fibres. pig. 36. capillary bloodvessels along the angles of junction, and sometimes between the contiguous sides. (Fig. 36.) Internal Structure. The beautiful cross-markings on the voluntary fibre have been known from the early days of microscopical research, and have given occasion to a variety of hypothe- tical and generally mechanical solutions of the problem of contraction ; which, by warping the minds of observers, have had the effect of greatly complicating an already difficult subject, that of the internal anatomy of the fibre, which can only be determined by pure observation. Fontana alone among the older anatomists abstained from vague speculation; and he arrived nearest to the truth. He found that the fibre was apt to split up into fine fibrilke, each of which was a series of particles; and he imagined that the transverse lines were caused by the regular apposition side by side of the particles of the contiguous fibrillge. It was customary both before and since his time, as at the present day, to regard the fibre as a bundle of smaller ones, whence the term