[124] Dr. Norris has recorded some striking observations in his paper on “Muscular Irritability” in the Journal of Anatomy, 1867, No. II. p. 217. Here is the only one I can find room for: “On taking up the dead frog and touching the limb (which during life had been paralysed by section of its nerve) with my finger, it was suddenly shot out as if alive. I placed the body down, and one or two apparently spontaneous movements of small extent afterwards occurred. On touching the skin gently with the point of a needle, by the slight pressure upon the muscle beneath, movements of the limb were also induced, but this high degree of exaltation very rapidly disappeared.”
[125] See their papers in the Archiv für Psychiatrie, 1875, Bd. V. Heft 3.
[126] This latter statement will be justified when I come to expound the Triple Process, which I have named the Psychological Spectrum.
[127] Foster and Balfour, Elements of Embryology, 1874, Part I. p. 52. His, Untersuchungen über die erste Anlage des Wirbelthierleibes, 1868, p. 197.
[128] They state that the cells of the epiblast are the results of direct segmentation, whereas the cells of the other layers are formed at a subsequent period, and are only indirectly results of segmentation. But if the observations of Kowalewsky are exact, this is not the case with the hypoblast of the Amphioxus, which is from the first identical with the epiblast.
[129] Kölliker, Entwicklungsgeschichte des Menschen und der höheren Thiere, 1861, p. 71.
[130] [According to Balfour’s recent observations, a large part of the muscular tissue is derived from the layer of the mesoblast belonging to the hypoblast.]
[131] His, Untersuchungen, pp. 39, 40.
[132] Quite recently Owsjannikow has pointed out the termination of fibres in the phosphorescent cells of the Lampyris Noctiluca. See his paper in the Mémoires de l’Acad. de St. Petersbourg, 1868, XI. 17. These phosphorescent cells are said to be ganglion-cells by Panceri, Intorno della luce che emana dalle celleule nervose (Rendiconto della Accad. delle Scienze, April, 1872); and by Eimer, Archiv für mikros. Anatomie, 1872, p. 653. Kölliker also calls the phosphorescent organ a nervous organ. This is not to be interpreted as meaning that neurility is phosphorescence, but simply that in some nerve-cells there is phosphorescent matter, which is called into activity by stimulus of the nerves.
[133] Bidder und Kupffer, Textur des Rückenmarks, 1857, p. 108. [What is said in the text has been rendered doubtful by the recent researches of Mr. F. Balfour, On the Development of the Spinal Nerves in Elasmobranch Fishes (Philos. Trans., Vol. CLXVI. Part I.), which show that in these fishes the ganglion has its origin in the spinal cord.]