It is remarkable that Mr. Darwin brings forward in support of gemmule fission, the observation that "Thuret has seen the zoospore of an alga divide itself, and both halves germinate.
Every gemmule may multiply itself by a process of scission into any number of equivalent gemmules.
We can easily conceive a being so small, that a gemmule would be to it as large as St. Paul's would be to us.
By means of the germinative affinity, every gemmule (except in cases of anomalies or monstrosities) can be developed only in cells homologous with the mother-cells of the cell from which they originated.
Any part of a gemmule would be an impossible (because a less than possible) quantity.
It is easily distinguished from all others by the fact that the birotulate spicules of the gemmule are of two quite distinct kinds, which occur together on every mature gemmule.
Gemmule of Spongilla bombayensis as seen from above (from type specimen), magnified.
In the case of floating buds the course of development is the same, except that the osculum, as in the case of development from the gemmule in other species (see Zykoff, Biol.
Each gemmule is covered with a thick chitinous membrane in close contact with its wall and surrounding it completely.
Internally the gemmule consists of a mass of cells containing food-material in what may be called a tabloid form, for it consists of minutely granular plate-like bodies.
Gemmule of Spongilla proliferens as seen in optical section (from Calcutta), x 140.
Gemmule with two layers of gemmule-spicules, the outer of which contains spicules of much greater size than the inner.
The fullest account of development from the gemmule as yet published is by Zykoff, and refers to Ephydatia in Europe (Biol.
The gemmule of a Zoophyte, which during its locomotive stage is distinguishable only into outer and inner tissues, no sooner takes root than its upper end begins to assume a different structure from its lower.
In the offspring, as soon as any particular cell or unit in the proper order of development becomes partially developed, it unites with (or to speak metaphorically is fertilised by) the gemmule of the next succeeding cell, and so onwards.
It has also been assumed that the development of each gemmuledepends on its union with another cell or unit which has just commenced its development, and which, from preceding it in order of growth, is of a somewhat different nature.
The assumed elective affinity of each gemmule for that particular cell which precedes it in the order of development is supported by many analogies.
Even in so simple a case as that of a perfect cell, with its protoplasmic contents, nucleus, nucleolus, and walls, we do not know whether or not its development depends on a compound gemmule derived from each part.
It has also been assumed that the development of each gemmule depends on its union with another cell or unit which has just commenced its development, and which precedes it in due order of growth.
The assumed elective affinity of each gemmule for that particular cell which precedes it in due order of development is supported by many analogies.
Perhaps Darwin’s gemmules may be suggested; but each gemmule represents a cell, while here we have to do with molecules or groups of molecules.
We must therefore assume the existence of a special gemmule for each group of molecules, and thus the innumerable gemmules of Darwin’s theory must be imagined as increased by many millions.
As a theory the gemmule plot is just as good and just as bad scientifically as Weismann's.
Darwin's Gemmule Theory is the same guessing; and Weismann rejects it because he did not think of it first.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "gemmule" in a variety of sentences. We hope that you will now be able to make sentences using this word.
