gemmule

Noun

gemmule (plural gemmules)

1. (archaic) Synonym of gemma (“an asexual reproductive structure, as found in animals such as hydra (genus Hydra) and plants such as liverworts (division Marchantiophyta), consisting of a cluster of cells from which a new individual can develop”)
   • A very similar mode of growth and propagation is found among the compound Polypes, whose gemmules, like those of the Medusæ, are at first free, and moved by cilia; afterwards attached, and budding forth with a plant-like body.1849, W[illiam] H[enry] Harvey, “The Microscopic Wonders of the Sea”, in The Sea-side Book; being an Introduction to the Natural History of the British Coasts, London: John Van Voorst, […], →OCLC...
   • Accidental hematozoa may be found, […] in the vessels of man and other animals; these are foreign to the blood, and do not circulate with it. The hydatid, acephalocystis endogena, detaches its gemmules from its inner surface; one thus inclosing the other in a series, like pill-boxes. It is found in...1855, Samuel Henry Dickson, “Exciting Causes of Disease. [Parasites—Animal and Vegetable.]”, in Elements of Medicine: A Compendious View of Pathology and Therapeutics; or The History and Treatment of...

   Synonyms:

   gemma

   1. (archaic, specifically) A small gemma or bud of dormant embryonic cells produced by some freshwater sponges (phylum Porifera) that develops into a new sponge.
      • Sponges are propagated by gemmules, which originate in the organic mucus, and are carried out of the body by the effluent currents just described. In some sponges these gemmules are ciliated and locomotive when mature; but it seems probable that the majority of the species produce only unciliated...1860, G. J., J. Y. J., “ZOOPHYTES”, in The Encyclopædia Britannica, or Dictionary of Arts, Sciences, and General Literature. […], 8th edition, volume XXI, Edinburgh: Adam and Charles Black, →OCLC...
      • The increase in size of the gemmule takes place by means of cell growth and division, and by the fusion of neighboring small gemmules.1891 July–December, Henry V[an Peters] Wilson, “Notes on the Development of Some Sponges”, in Journal of the Elisha Mitchell Scientific Society, volume VIII, part 2, Raleigh, N.C.: E. M. Ezzell, […]...
2. (historical) In the obsolete theory of pangenesis propounded by the English scientist Charles Darwin (1809–1882): a hypothetical particle once thought to be the basis of heredity.
   • […] I assume that cells, before their conversion into completely passive or "formed material," throw off minute granules or atoms, which circulate freely throughout the system, and when supplied with proper nutriment multiply by self-division, subsequently becoming developed into cells like those...1868, Charles Darwin, “Provisional Hypothesis of Pangenesis”, in The Variation of Animals and Plants Under Domestication. […], volume II, London: John Murray, […], →OCLC, part II, page 374
   • Curse you, you wandering gemmule, / And nail you fast in Hell! / You gave me gout and bandy legs, / You beast, you wanted a cell! / Gout, and gravel, and evil days— / (Theology speaks, shaking her head) / But there is One who knows your ways!1868, Alfred, Lord Tennyson, “Darwin’s Gemmule”; quoted in Christopher Ricks, “Tennyson Inheriting the Earth”, in Hallam Tennyson, editor, Studies in Tennyson, Totowa, N.J.: Barnes & Noble Books...
3. Synonym of plumule (“the first bud, or growing point, of a plant embryo, situated above the cotyledons”).
   • To what do this cavity which contains the gemmule, this thin layer which covers it, correspond? We have stated that the cotyledon is nothing else than the first leaf of the little vegetable, and the gemmule the union of the leaves which will follow it.1849, Adrien[-Henri] de Jussieu, “Ovule and Seed”, in James Hewetson Wilson, transl., The Elements of Botany, London: John Van Voorst, […], →OCLC, § 579 (Monocotyledonous Embryo), page 442
   • The embryo is composed of cells and spiral vessels; a small stem, or stalklet; a rudimentary descending portion, which becomes the root or radicle; and a rudimentary ascending axis, surrounded by a bud, or gemmule. Between the radicle and the gemmule, the first leaves developed are termed...1867, Louis Figuier, “The Fruit”, in [anonymous], transl., The Vegetable World; being a History of Plants, with Their Botanical Descriptions and Peculiar Properties. […], London: Chapman and Hall...

   Synonyms:

   plumule

4. Synonym of dendritic spine (“a small membranous protrusion from the dendrite of a neuron that typically receives input from a single axon at the synapse”).
   • Concussion from shell explosion often sufficient to produce miliary hemorrhages in brain substance. Mott has found such lesions in brains of shell shock. Lesser lesions on fine nerve fibrils and gemmules, or nerve cells may reasonably be postulated.1927, William N[ewbold] Bispham, “Professional Schools in Military and Nonmilitary Institutions”, in Frank W. Weed, editor, The Medical Department of the United States Army in the World War, volume...
   • The mitral cells also extend several secondary dendrites (SD) laterally outward into the external plexiform layer (EPL), where they are in intimate association with the dendritic spines (or gemmules) belonging to the dendrites of the granule cell population, whose cell bodies (g) lie deeper in the...1981, Wilfrid Rall, “Functional Aspects of Neuronal Geometry”, in Alan [Madoc] Roberts, Brian M. H. Bush, editors, Neurones without Impulses: Their Significance for Vertebrate and Invertebrate...

   Synonyms:

   dendritic spine