Word: gemmule Part of Speech: noun Etymology: Borrowed from French gemmule, from Latin gemmula (“small bud; small gem”), from gemma (“bud of a plant; gem, jewel; thing made of precious stones”) (further etymology uncertain; possibly from Proto-Indo-European *ǵenh₁- (“to beget, give birth; to produce”), but see further at that entry) + -ula (feminine form of -ulus (diminutive suffix)). Pronunciation: /ˈd͡ʒɛmjuːl/, /ˈd͡ʒɛˌm(j)ul/ 1. 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”) Labels: archaic Example: 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. Example: 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 the liver, kidney, womb, etc. 2. 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”) Labels: archaic, specifically Example: 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 gelatinous grains, which are nevertheless endowed with a very active motility, like the ultimate particles of even inorganic matter. Example: The increase in size of the gemmule takes place by means of cell growth and division, and by the fusion of neighboring small gemmules. 3. 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. Labels: historical Example: […] 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 from which they were derived. These granules for the sake of distinctness may be called cell-gemmules, or, as the cellular theory is not fully established, simply gemmules. […] Their development is supposed to depend on their union with other partially developed cells or gemmules which precede them in the regular course of growth. […] Lastly, I assume that the gemmules in their dormant state have a mutual affinity for each other, leading to their aggregation either into buds or into the sexual elements. Example: 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! 4. Synonym of plumule (“the first bud, or growing point, of a plant embryo, situated above the cotyledons”). Example: 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. Example: 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 cotyledons: a plant having leaves like seed-lobes. 5. 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”). Example: 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. Example: 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 granular layer (GRL) of the bulb.