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]
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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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    the explanation of such problems of cell structure and contractility as those briefly enumerated above. On this view, the granules of such a low vegetable organism as Torula (disregarding, of course, sap vacuoles and fat globules) are aggregation products, an assumption by no means excessive, espe- cially when we bear in mind the activity of the chemical changes •which are going on during its life and growth. But if this step be taken, we cannot resist regarding the Amoeba in the same way ; its granules too are aggregation products, and the clear ectoplasm, when present, may be viewed as protoplasm in which aggregation is not occurring. The variations of amoeboid organisms in more or less granular character (a fact familiar to every observer) is thus brought into obvious relation with the state of nutrition, or with the quality and quantity of external stimuli; and its observed increase when stimulated, and its diminution during the resting state, are thus naturally accounted for. In the same way, in the granular pseudopodia of the Eoraminifera, aggregation is in progress, in the hyaline processes of the Heliozoon not so. The granules of cells in higher animals may be, at least to a very large extent, similarly explained; while the disputes as to the presence or absence of a stroma become clearer when we bear in mind the fact that Darwin's aggregation-masses are at least as often greatly elongated or spherical, and that they may run in any direction, and unite or separate to any extent. The remarkable differentiations of protoplasm visible during cell-division, as exhibited by ova (of course excluding yolk granules, &c), may not improbably admit of the same explanation. 3. Contractile Structures—Muscle.—The excessively difficult problem of muscular structure has not as yet received any widely- accepted solution, and even respecting matters of observation the widest discrepancies exist. In many invertebrates we cannot even be certain whether the muscles are striped or non-striped, so contra- dictory are the observations, while in a recent important paper by Professor Haycraf t,* the homogeneity even of striated muscle is main- tained. Brilliant light has, however, been lately thrown upon the arena of controversy by Professor Kuthcrford's recent elaborate demonstration f that the discrepancies in observation arc largely * Proc. Roy. Soc. Lond., 1881. t Proc. Roy. Soc. Edin., 1883.