[9] The authorities just cited are Aristotle, De Anima, Lib. II. c. I. Kant, Kritik der Urtheilskraft. Müller, Physiology. Beale, Bioplasm, and Introduction to Todd and Bowman’s Anatomy. Schelling, Erster Entwurf, and Transcendent. Idealismus. Bichat, Recherches sur la Vie et la Mort. Stahl, Theoria Vera Medica. Dugès, Physiologie Comparée. Béclard, Anatomie Générale. Lamarck, Philosophie Zoologique. Comte, Cours de Philosophie Positive. Owen’s Hunterian Lectures, 1854. Herbert Spencer, Principles of Biology.
[10] Fletcher, as quoted by Drysdale, Life and the Equivalence of Force, Part II. p. 120.
[11] Robin et Verdeil, Traité de Chimie Anatomique, 1853.
[12] Paget, Lectures on Surgical Pathology, p. 14.
[13] Comp. Haeckel, in Siebold und Kölliker’s Zeitschrift, 1865, p. 342, and his Generelle Morphologie, 1866, I, 135, 336.
[14] In the Archiv für mikros. Anatomie, 1865, p. 211.
[15] Here organization is the simplest form of all—molecular organized structure, which in the higher forms becomes tissue structure, and organ structure. The word structure properly means orderly arrangement of different materials; and molecular structure refers to the different proximate principles which constitute the organized substance. Usually, however, the word structureless indicates the absence of visible arrangement of the parts; a cell has structure since it has nucleus and protoplasm.
[16] In the cell-theory established by Schleiden and Schwann, in 1838, and which has formed the basis of modern histology, the cell-wall was endowed with an importance which can no longer be upheld now that the existence of independent organisms, and of cells, without a trace of enveloping membrane has been abundantly observed. Cells without walls were first described by Coste in the Comptes Rendus, 1845, p. 1372. They were also described by Charles Robin in 1855, Dict. de la Médicine, art. Cellule. But little notice was taken until Max Schultze, in his famous essay, Ueber Muskelkörperchen und was man eine Zelle zu nennen habe, which appeared in Reichert und Du Bois Reymond’s Archiv, 1861,—Bruecke, in his memoir, Die Elementarorganismen, 1861,—and Lionel Beale, in his Structure of the Simple Tissues, 1861,—all about the same time began the reform in the cell-theory which has effected a decisive change in the classical teaching. Leydig claims, and with justice, to have furnished important data in this direction (Vom Bau des thierischen Körpers, 1864, I. p. 11). The student interested in this discussion should consult Max Schultze, Das Protoplasma der Rhizopoden und der Pflanzenzellen, 1863; Haeckel, Die Radiolarien, 1862; the controversial papers by Reichert, in his Archiv (beginning with the Report of 1863), and Max Schultze, in his Archiv für mikros. Anat., with Henle’s judgment in his Jahresberichte, and Külliker’s summing-up in the last edition of his Gewebelehre. For a full yet brief history of the cell-theory see Drysdale, The Protoplasmic Theory of Life, 1874, pp. 96–106.
[17] At the time this was written, I had some fish ova in the course of development. Out of the same mass, and in the same vessel, all those which were supported by weed at a depth of half an inch from the surface, lived and developed; all those, without exception, that were at a depth of two to four inches, perished. In ordinary parlance, surely, nothing would be objected to in the phrase, “these ova were all in the same Medium”; the water was the same, the weed the same, the vessel the same; yet some difference of temperature and carbonic acid made all the difference between life and death. Another curious fact was observed; I removed eight of these ova with active embryos, and placed them in a large watch-glass containing a solution (one half per cent) of bichromate of ammonia. In this acid the embryos lived and were active fifty-seven hours, although other embryos placed in a similar watch-glass containing pond-water, survived only forty hours. The non-effect of the acid was probably due to the non-absorption which nullifies the effect of certain virulent poisons when they are swallowed; but why the fish should live longer in the acid than in the simple water, I do not at all comprehend.
[18] Agassiz, Essay on Classification, 1859, p. 15.