A re-statement of the cell theory : with applications to the morphology, classification, and physiology of protists, plants, and animals : together with an hypothesis of cell-structure, and an hypothesis of contractility / by Patrick Geddes.

Date:
[1884]
Catalogue details

Licence: Public Domain Mark

Credit: A re-statement of the cell theory : with applications to the morphology, classification, and physiology of protists, plants, and animals : together with an hypothesis of cell-structure, and an hypothesis of contractility / by Patrick Geddes. 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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    a contracted amoeba), as representing the amoeboid form. A distinct assumption of the amoeboid state at the close of the ciliated one, is sometimes to be observed,—as lately by Reinke* in Bangia. And thus the cycle is complete, save only for the plasmodial phase. The importance of this view for the Protophytes then, is scarcely less than for the Protozoa. With a tendency of the encysted state to predominance, more marked even than in the Gregarines, the other phases are by no means obliterated, and we thus—and only thus— obtain an intelligible explanation of that alternation between the resting and the motile phase which is so frequent and so charac- teristic. The inevitable applicability of this to classification, and the light it yields, will be sufficiently obvious. Without prematurely proposing a detailed classification, it will be obvious that we must regard those forms, which like Torula, exhibit only the resting state, not as primitive, but as exceedingly specialised, and those which exhibit more and more of the cycle as less so. 3. Affinities of the Myxomycetes.—Passing to the Myxomycetes, it will at once be evident, that unless the present theory can be entirely overturned, they have no place among the fungi proper— where it is the encysted phase that predominates, the others being greatly reduced or suppressed; but are in fact morphologically as remote from these as are the monads. The Myxomycetes must be placed next Protomyxa; in fact, Protomyxa is simply the least differentiated known Myxomycete. Their higher forms are interest- ing—first, in very frequently showing less of the ciliated stage, and secondly (a more important character, since here they are unique among living beings), in affording an enormous differentiation of their plasmodial stage ; the complicated forms which many of them exhibit being simply those of their plasmodial froth, to which per- manent shape is then given by the formation of a cellulose envelope. The resemblance to fungi is thus as purely superficial and adaptive as that, for instance, of Hydroids to Polyzoa, and, like it, is of physio- logical interest alone. 4. The Protista.—The general non-adoption of Hseckel's pro- posal of a third intermediate Reg mm Protisticum, has been due to three main reasons,—of which the first is that the proposal seems only to doubly the difficulty, since it does not enable us to distinguish * Mitthcil. d. Zool. Stat, intfcapcl., 1883.