Recent advances in the physiology of motion, the senses, generation, and development. Being a supplement to the second volume of Professor Muller's "Elements of physiology". / by William Baly and William Senhouse Kirkes.
- Date:
- 1848
Licence: Public Domain Mark
Credit: Recent advances in the physiology of motion, the senses, generation, and development. Being a supplement to the second volume of Professor Muller's "Elements of physiology". / by William Baly and William Senhouse Kirkes. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
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![DEVELOPMENT OF NEIIVE-FIBRES. Several new Facts have also been added concerning the development of nerves, which tend to throw fresh light on the physiology of the nervous system, since they render it almost certain that the central ter- minations (or origin) of nerve-fibres are not disposed in loops, as until lately has been generally supposed to he the case, hut that they pass directly into the nerve-corpuscles which compose so large a portion of the grey substance of nervous centres. Both Muller and Remak, several years ago, observed that from some of the corpuscles of the grey sub- stance of the brain, spinal cord, and ganglia, fine tooth-like processes issue, and may be sometimes traced to the extent of many times the diameter of the corpuscles.* The resemblance which these processes bear to the delicate, grey filaments observed by Remak in the sympathetic nerves, led to the suggestion that the two are identical, and that the latter filaments take their origin directly from the ganglion corpuscles. These observations, however, do not appear to have attracted much further notice; but it has been found by more recent investigations, that Remak’s sugges- tion concerning the origin of sympathetic nerve-fibres is perfectly correct, and moreover that the fibres of the cerebro-spinal nerves also have, as was indicated by Ehrenberg,f an exactly similar origin.]; Without entering into the details of these important investigations, the consideration of which would be foreign to the present purpose, it may be remarked that in the junction of the nerve-fibres with the ganglion-corpuscles, the contents of the central part of the fibre (the axis-cylinder of Purkinje and Rosen- thal, the primitive hand of Remak) pass directly into the granular contents of the corpuscle, while the fine external sheath of the nerve-fibre becomes continuous with the membranous envelope, within which the granular substance of the corpuscle is contained. The phenomena observed during the development of nerve-fibres in the embryo, especially by Schaffner § and Kolliker, |( agree very closely with these facts. In the earliest period of its formation nerve-suhstance consists almost entirely of roundish, mostly nucleated cells filled with a finely granular material, and, with the excep- tion of being somewhat smaller, exactly similar to the nerve-corpuscles found in the nervous centres of the adult animal. As the development proceeds, but previous to the appearance of distinct nerve-fibres, many of these cells send forth fine tubular processes of an apparently homogeneous structure, which unite with similar processes from other cells, and thus, in time, give rise to continuous nerve-tubules. Kolliker finds that in young * Miiller’s Physiology, vol. i. p. G57. + Stnictur des Seelenorgans. Berlin, 1836. + See Helmholtz, de Fabric. System. Nerv. evertebratorum. 1842 ; Kolliker, die Selbstand. und Abhang. des sympath. nervensyst. Zurich, 1844 ; Dr. Will, in Muller’s Archiv. 1844 ; Dr. Todd and Mr. Bowman, Physiological Anatomy of Man, vol. i. p. 213; and more especially R. Wagner, Neue untersuchungen Uber den Bau und die endigung der Nerven und die Struktur der Ganglion, Leipzig, 1847, and Dr. F. II. Bidder, zur Lehre von dem Nerven- fasern. Leipsig, 1847. § Schmidt’s JahrbUcher, 1847. |] An. des Sc. Nat. Zoologie, 1846, p. 104.](https://iiif.wellcomecollection.org/image/b21967660_0138.jp2/full/800%2C/0/default.jpg)
