Embryology, with the physiology of generation ... / Translated from the German, with notes, by William Baly ... From Müller's Elements of physiology and supplement.

  • Johannes Peter Müller
Date:
1848
Catalogue details

Licence: Public Domain Mark

Credit: Embryology, with the physiology of generation ... / Translated from the German, with notes, by William Baly ... From Müller's Elements of physiology and supplement. Source: Wellcome Collection.

    29/376 page 1429
    GROWTH OF FUNGI. ner; while all other parts of their body, however large or small, are destitute of the reproductive power. In those plants and animals which propagate their species by buds or sprouts, the germ consists of a mass of cells which may be produced at almost any part of the body of the parent. In some of the lower animals the same reproductive power is possessed by every aggregate of organic elementary parts, that is, of such elementary parts as were originally developed from similar cells, but which subsequently have acquired the form and properties of mus¬ cular and nervous fibres, and of fibres of cellular tissue, &c. In the lowest organic beings the power of producing new individuals is not merely manifested by separate portions of most parts of the body, but in some cases subdivision, even into the ultimate particles of the organism, does not destroy this power : isolated elementary particles are adequate to the propagation of the species. In plants, generally, all the tissues are produced from cells; but there are plants in which any single cell separated from the rest of the organism, suffices for the reproduction of the entire plant, if nutritive matter be supplied. We have examples of this in the filiform fungi, such as the fungus of mould and the vegetable product, which, according to the observations of Cagniard Latour and Schwann, forms the active part of yeast, and the growth of which in large quantity gives rise to the fermentation of saccharine liquors. This fungus of yeast consists of cells arranged in simple or branched threads; and it grows by some of the cells developing upon their free surface a small prominence which becomes a young cell. This young cell soon attains the perfect size, but has scarcely reached its full development before it, in its turn, begins to put forth a bud, which is the germ of the next cell. (See fig. 149, p. 1436.) Single cells of this kind also separate them¬ selves from the threads of which they formed part, and still in the iso¬ lated state form new cells by the process of budding, and thus propagate their species. All this process takes place so rapidly, that its different steps may be watched by means of the microscope.* The same pheno¬ mena are presented by all the simple fungi. The dust-like powder of the fungus so destructive to silkworms, the muscardine, is composed of cells endowed with the power of reproducing plants of the same species; hence we may easily conceive that a single grain or cell of this powder, introduced into a brood of silk-worms, may cause their entire destruction.f CHAPTER II. OF THE MULTIPLICATIONS OF INDIVIDUALS BY THE DIVISION OF PERFECTLY DEVELOPED ORGANISMS_FISSIPAROUS GENERATION. Since organic beings in the fully developed condition are virtually multiples of the germ which produced them, they are capable of multi- -|- See Audouin, Annal. des Scienc. Nat. 1837. 5 B * Poggendorf’s Analen, xli. p. 184.
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