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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    not make it a simple substance. Combinations of Cellulosewith other bodies are not yet known; there thus remains, to explain the easy transition of Cellulose into Sugar, Dextrin, and Starch, only the hypothesis of Iso- merism. All other formulae appear purely arbitrary, and explain nothing, for the elementary analyses vary from 43-22 to 52-01 of carbon, 5-9 to 6'91 hydrogen, 41*57 to 50-38 oxygen, or of analyses of the same cellular tissue taken into account C 43*2—44*7, II 6-0—6*5, O 493—50-59, which agree perfectly with the formula given above. On the other hand, the whole doctrine of an incrusting matter (Payen), although supported by the profundity of Mulder (Physiol. Chem. Moleschott, p. 209.), is a mere castle in the air, that must be rejected a priori. On the application of the ordinary re-agents, the thickness of the cell-walls is not diminished, but they become loosened and swell up. What the reagents take up are the contents of the cell, and matters which the cell-wall contain, and which, according to the age of the cell, would become colouring matter, tannin, humic acid, and humates. The wood-cells are, in comparison with other cells, decaying, and are constantly forming out of the cellulose substances, which are more and more rich in carbon, which remain dis- solved in the cell-walls, and which ai*e taken up by means of re-agents. The successive layers of the cell-wall are composed chemically out of the same or an isomeric matter as the primary cell, which explains its whole deportment, and even Payen’s elementary analysis of the spiral fibres in Musa sapientum. A knowledge of the cell-layers is especially important physiologically ; a knowledge of the substances which convert sap-wood into heart-wood is only technical, as here life is almost wholly extinct. Cellulose presents itself under many modifications. In its pure state it appears to vary chemically, according to the quantity of water it con- tains. Independently of this, it varies greatly in its physical properties, such as brittleness, viscosity, density, and especially in its perviousness to water, which the less it is the more it appears to approach in its nature amyloid and jelly ; and there ai*e, in fact, very many transitionary bodies between these three.* In the impure state in which it ordinarily occurs, it varies yet more from the passage through it of other matters ; perhaps through some de- composition which they induce. Its colour is especially various, passing from perfect transparency to the darkest brown (as in ferns); and occa- sionally all other possible colours are present, as is seen in the epidermis of the seeds of Leguminosce, a golden yellow colour in the leaves of Flior- mium tenax, he. 2. Amyloid f is, when dry, a cartilaginous, but moist, gelatinous, clear, transparent body, soluble in boiling water, strong acids, and caustic alkalies, but not in ether and alcohol in a concentrated state. It is coloured blue by iodine, and the combination is soluble in water, giving it a golden-yellow colour. It is found only in the layers of the primary cell-membrane. There is no chemical analysis of this substance. It has been found at present only in the cotyledon-celIs of Schotia latifolia, S. speciosa, Ilymencea Courbaril, Mucuna urens,M. gigantea, and Tama- rindus indica. Perhaps many of the observations of Hugo Mold belong to this substance. 3. Vegetable Jelly (Vegetable Mucilage, in part, of the chemists, Bas- * See Hugo Mohl, Some Observations upon the blue Colouring of vegetable Cell Membrane, through Iodine. Flora, 1840. f See Poggenclorfl’s Annalen, 1839.