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

Date:
1849
Catalogue details

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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    taining tlie activity of the embryo until the time comes for its development. Their cells contain either less mucus but more starch, as in the leguminous cotyledons, and in the albumen of the Cerecilia; or they contain more mucus and, instead of starch, a fat oil, as in the cotyledons of the Cruciferce and in the albumen of some Palms and Euphorbiacece; or lastly, they contain scarcely any mucus, but their walls are strikingly thickened, and the cellulose is found not to possess its usual physical condition, or is in some way chemically distinct. It is more easily dissolved and decomposed than usual. This is seen in some leguminous cotyledons, as, for example, in the Tamarind, in the albumen of many Palms, as the Date-palm, and in a most striking degree in the Ivory-nut (P/njtelephas). From this it results that we have six principal conditions, without mentioning the intermediate states, which demand an accurate investigation. Hitherto no microscopic and chemical history of germination has been given with any accuracy or completeness; we are still in the infancy of our knowledge respecting it. For the most part, chemists understand nothing of micro- scopic physiology, and botanists little of chemistry. Hence there has been no harmonious pursuit of science between them, the absence of which has retarded both, so that we neither possess, nor are on the eve of possessing, a complete and fundamental knowledge of the history of germination. The reason of our ignorance on this subject arises from the fact, that in investigating it the chief attention has been turned upon that point where the difficulty does not exist. The development of the young plant will be explained when we shall have explained the life of the plant in general. The principal difficulty that requires explanation is how the conditions, which in an embryo result in a definite process, remain for a long time suspended. If we place a ripe acorn in the soil, under all the circumstances requisite to germination, why do not those chemical pro- cesses which excite germination and development immediately take place ? In this case chemical processes slowly go on in the interior of the cells, with which we are as yet altogether unacquainted ; and perhaps, also, the structure of the cells, or the chemical nature of their contents, is such as to make the operation of external agencies only very slowly effective. The Coffee-bean does not germinate at all, unless it is placed in the requi- site circumstances immediately upon its ripening. Wheat has been proved, by the experiments of Sternberg, to germinate after it had lain inactive for three thousand years.* Many facts must be collected, and the most minute chemical investigations must be made respecting the con- tents of the cells and the cell-walls, the structure of the embryo must be accurately examined, before we can obtain correct results : all else is but theoretic dreaming. Only confusion or uncertainty can be expected where so much, if not all, is yet to be investigated. Thus much, however, we have ascertained teleologically, namely, that the cells of the embryo and the albumen are completely filled with as- similated matters, in order to prevent, during the drying of the cells, their crushing together, and thus to make their future active life possible. Of these matters, a considerable portion is not only superfluous to the support ol the life of the embryo, but is actually in the way, and when germination commences it is disposed of by being converted into carbonic acid and water. To this atmospheric oxygen is essential, and also, as in every other chemical piocess, a certain amount of heat and moisture, and these lie made wheat taken fioin the coffins of mummies to germinate, and the same has >ecn done in England, [ the circumstances under which this has taken place, in Eng- land at least, are not free from suspicion Trans.]