Descriptive catalogue of microscopical specimens, illustrating the structure of certain tissues and organs of man and animals in health and disease, exhibited at the President's soirée, in the University Museum, August 5th 1868 / by Lionel S. Beale.

Beale, Lionel S. (Lionel Smith), 1828-1906.

Date:: 1868

Credit: Descriptive catalogue of microscopical specimens, illustrating the structure of certain tissues and organs of man and animals in health and disease, exhibited at the President's soirée, in the University Museum, August 5th 1868 / by Lionel S. Beale. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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$figs. 31, 32, and 33 may be compared with Kiiline’s drawings, figs. 18, 19, 20, and 21, and Kolliker’s fig. 24, in all of which the nerve is supposed to end. To Kiihne is undoubtedly due the merit of having observed the so-called end plates or end organs in voluntary muscle, and it is not surprising that he should have been led to regard them as the special nerve organs of this tissue. He has studied principally large muscular fibres, and considers these most favourable for observation, but it seems not to have occurred to him that in consequence of the refractive power of the contractile tissue, the finer nerve fibres may be completely obscured. I do not think he has yet formed the slightest idea of the general arrangement and great number of the fine nerve fibres in voluntary muscle, as may be demonstrated, for example, in the delicate mylohyoid muscle of the hyla, pi. VIII. At least in the chameleon several fibres are to be seen passing to and from each nerve tuft, but Kiihne has only figured a single dark-bordered fibre entering the tuft. These ‘ tufts ’ may be compressed nerve loops or networks, but they cannot be end organs. In them the nerve does not end. See figs. 25, 26, 27, 28, pi. VI. It seems to me most probable that these bodies are exceptional and not present in all muscles, nor essential to voluntary muscle generally. As in other tissues the peripheral arrangement of the nerves in voluntary muscle is a continuous network, in which the nearest approach to an ‘ end ’ or ‘ termination ’ is a loop. See figs. 31, 32, 33. Kiihne is also wrong in concluding that the nerve tuft is situated beneath the sarcolemma and in contact with the contractile tissue. Like many of the nerves these bodies adhere to the sarcolemma, but are certainly not in intimate relation with the contractile material of the muscle. In pi. VI, ‘nerve tufts’ exhibiting various degrees of complexity are represented. The course of the exceedingly fine nerve fibres can be followed and their connec- tion with the nuclei demonstrated. The general conclusions I have arrived at from investigating the structure of these bodies accord very closely with those resulting from investigations upon other tissues. * 50. Ultimate Distribution of finest nerves as networks and plexuses in the mylohyoid muscle of the hyla or green tree frog. These fibres are very narrow, and at the same time each is separated by a distinct interval from its neighbours. See pis. VII and VIII, figs. 30, 33. The state of things is, therefore, very favour- able for the observation of the oval end organs if they are present. I have never been able to discover one in this beautiful example of voluntary muscle, though I have found them in many other specimens of muscle. Nerve fibres may be traced for an immense distance from the bundles of dark-bordered fibres. Gradually they become less than the 10oono of an inch in diameter, figs. 31, 33, but still divide and subdivide into fine threads with oval nuclei at intervals, now running parallel with the muscular fibre, then crossing it, dividing into branches, some of which after pursuing a very long course may at last be traced to a dark- bordered fibre in another part of the muscle. I have succeeded in doing this in many different specimens, but other observers have failed to confirm my observa- tions, as regards voluntary muscle, although they admit their correctness in the case of involuntary muscle. The failure of others to obtain specimens exhib- iting the same appearances no doubt depends upon a very different method of investigation having been pursued. Anatomists in Germany have not only failed$