[162] Luys, Recherches sur le Système nerveux, 1865, p. 267. In a recent and remarkable treatise the student is informed that “plus une cellule est chargée d’un rôle purement mécanique plus elle est volumineuse; plus l’acte qu’elle produit tend à revêtir un caractère psychique plus elle est petite”; to move a limb the agitation of the cerebral cells must materialize itself more and more, “Il a besoin de passer par des cellules, de moins en moins spirituelles et de plus en plus matérielles.... De même pour les cellules sensitives. L’impression extérieure va en se modifiant, en se spiritualisant, de la périphérie au centre.... Un phénomène de l’ordre spirituel ne sanrait devenir sans transition un phénomène d’ordre physique.” And what is this marvellous transition between spiritual and physical? It is the action of medium-sized cells which “travaillent la vibration reçue, la modifient de façon à lui ôter de son spiritualisme et à la rapprocher davantage des ébranlements physiques.” I will not name the estimable author, because he is simply restating what many others implicitly or explicitly teach; but I will only ask the reader to try and realize in thought the process thus described.
[163] Schröder Van Der Kolk, Pathologie der Geisteskrankheiten, 1863, p. 69.
[164] Wundt, Physiologische Psychologie, p. 261. In his Mechanik der Nerven, 2 Abth. (published just as this sheet is going to press), he shows that a stimulus is both retarded and weakened in its passage through a ganglion.
[165] Trinchese also says that the fibres “provengono dalle cellule e non son altro che i loro prolungamenti o poli.”—Op. cit., p. 13. An unequivocal example is seen in the Torpedo, where the large cells have each their prolongation continuing without interruption into the electrical organ. See the figure given by Reichenheim in the Archiv für Anat., 1873, Heft VI.
[166] Golgi, Sulla struttura della sostanza grizia del Cervello. Arndt, Archiv für mikros. Anat. 1870, p. 176. Rindfleisch also traces these processes into the neuroglia (ibid., 1872, p. 453). “Deiters, Boddaert, and other observers have stated that one dark-bordered nerve-fibre enters each cell.... My own observations lead me to conclude that all the fibres are composed of the same material, but that one fibre does not divide until it has passed some distance from the cell, while others give off branches much closer to it.”—Beale, Bioplasm, p. 189.
[167] Beale, Bioplasm, p. 177. Max Schultze, in Stricker’s Handbuch, p. 134. Comp. Stilling, Nervenprimitiv-Faser, p. 133. Arndt, Archiv für mikros. Anat., 1868, p. 512; and 1869, p. 237. Weighty as these authorities are, their view is questionable—firstly, because the forms of these cells are too constant and definite in particular places to result from the union of fibrils coming from various origins; but secondly, and mainly, because the teaching of Development is opposed to it.
[168] Robin, Anat. et Physiol. Cellulaires, p. 335.
[169] Archives de Physiologie, 1872, p. 268.
[170] The fact of the existence of cells in the white substance is one which is very difficult of interpretation on the current hypotheses. The cells are found in regular columns and irregularly scattered. Boll thinks that while in the white substance of both cerebrum and cerebellum there are true nerve-cells as well as connective corpuscles, in the cord there are only the latter. But hitherto there has been no decisive test by which a nerve-cell can be distinguished from a connective corpuscle.
[171] Monthly Journal of Micros. Science, XI. 219. This accords with what Kupffer says respecting the entire absence of cells in the earliest stages observed by him in the sheep. The white substance of the spinal cord he describes as soft, transparent, and gelatinous, in which dark points are visible; these dark points are seen in longitudinal sections to arise from the fibrillation of the substance.—Bidder und Kupffer, Op. cit., p. 111.