On metamorphosis and metagenesis / Professor Owen.

  • Owen, Richard, Sir, 1804-1892.
Date:
[1851]
Catalogue details

Licence: Public Domain Mark

Credit: On metamorphosis and metagenesis / Professor Owen. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    in the body of the first individual developed from that germ-mass, with so much of the pollen-force inherited by the retained germ- cells from the parent-cell or germ-vesicle as suffices to.set on foot and maintain the same series of formative actions as those which constituted the individual containing them. How the retained pollen force operates in the formation of a new germ-mass from a secondary, tertiary, or quaternary derivative germ- cell, the Lecturer did not profess to explain ; neither was it known how it operates in developing the primary germ-mass. The botanist and physiologist congratulates himself with justice when he has been able to pass from cause to cause, until he arrives at the union of the pollen-filament with the ovule as the essential condition of development — a cause ready to operate when necessary circumstances concur, and without which those circumstances would have no effect. The chief aim of the present discourse was to point out the cir- cumstances which bring about the presence of the same essential cause in the cases of the development of the successive generations completing the inetagenetic cycle of the Aphis, the Medusa, the Polype and the Entozoon. The cause is the same in kind though not in degree, and every successive generation, or series of sponta- neous fissions, of the primary germ-cell must weaken the pollen-force transmitted to such successive generations of cells. The force is exhausted in proportion to the complexity and living powers of the organism developed from the primary germ-cell and germ-mass. It is consequently longest retained and furthest trans- mitted in the vegetable kingdom; the zoophytes manifest it in the next degree of force; and the power of retained germ-cells to de- velope a germ-mass and embryo by the remnant of the pollen-force which they inherited, is finally lost, according to present knowledge, in the class of Insecta and in the lower Mollusca. 1 Among the objects exhibited in the Library, were — Edwards’ Atmopyre or Gas Stove [by D. O. Edwards, Esq., M.R.I.] — Sketch of Coldham-hall, near Bury St. Edmunds, reproduced as a Photo- graph, coated with a solution of Gun-Cotton ; and several other Photographs from Etchings &c. —and a group of Garnets in Mica Schist from the Rocky Mountains, North America [by Dr. A. S. Taylor, M.R.I.]—Specimens of Sugar of Milk [by T. N. R. Mor- son, Esq., M. R. I.— Model of the Nineveh Column in the British Museum, in Hall’s Derbyshire black marble [by J. Tennant, Esq.] &c. &c.
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