Principles of scientific botany, or, Botany as an inductive science / by J.M. Schleiden ; translated by Edwin Lankester.

Date:
1849
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Licence: Public Domain Mark

Credit: Principles of scientific botany, or, Botany as an inductive science / by J.M. Schleiden ; translated by Edwin Lankester. 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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    History. We not unfrequently find examples in Science, of the unprejudiced glance of the first observer divining and expressing the truth, which, however, is naturally at once thrown aside by Science as unfounded and contradicting its temporary laws, till in the end it works back gradually to that first notion, but now consciously, and supported in every way by the true reasons. Thus, if we look to the result noAv secured as to the origin of the embryo, it is at the bottom exactly the same as that which was asserted more than a hundred years ago by Samuel Morland *, namely, that the pollen-tube descended through the style into the seed-bud and became the embryo. This notion, in its crude form, was contested, and, indeed, at that time, properly, by Vaillant and Patrick Blair. After that, all deeper investigation, such as had been roused by Malpighi, gradually fell asleep ; and when Treviranus f wrote his work on the Development of the Embryo, it was to be considered as a great advance, although he did not go beyond what Malpighi had done, and even did not reach many of the beautiful observations of Malpighi, e. g., the existence of the embryo-sac. The observation of the embryo in its earlier conditions, as the embryonal globule, from which Malpighi and Treviranus started, commenced with Ad. Brongniart (/. c.), and he very nearly completed the matter ; if he had only used the obser- vations of Robert Brown, which soon followed, and by means of these explained his observations on Momordica Elaterium, which only wanted an intermediate stage, easily added hypothetically, he would have dis- covered the origin of the embryo from the pollen tube penetrating into the embryo-sac. Thus the materials stood till IJ brought the matter to a conclusion by my researches. I regard it as wholly superfluous to report on the many opinions of those whose imagination was busier in spinning out their own discoveries, than their hands in dissecting or their eyes in observing accurately — people who in all ages have confused natural science instead of advancing it. B. THE DEVELOPMENT OF THE EMBRYONAL GLOBULE INTO THE EMBRYO. § 166. The main features of this section have necessarily been already given (§ 121.), but this is the place in which to enter into this matter somewhat more specifically ; for this purpose it seems requisite to separate the Monocotyledons from the Dicotyledons, and the Gymnosperms from both. As an universal law, valid for all Phanerogamia, there is only one thing to be expressed, that the part of the embryonal globule corresponding to the point of the pollen-tube always becomes the bud; the opposite part therefore, of course, that turned toward the apex of the embryo-sac, the nuclear papilla and micropyle, becomes the radicle. The existence of this law of position of the radicle in the seed-bud was first stated by Robert Brown. * New Observations on the Parts and ] 70S. Use of the Flower in Plants. Phil. Trans., Von der Entwick. des Embryo, See. Berlin, 1817 Einige Blicke auf die Entwickl. des veg. Organismus, i. p. 289.; Ueber Bildung des Eichens und Entstelmng L. C. vol. xix. p. 1 ° Wiegmann’s Archiv, 1887, des Embryo, Act. Acad.