On the supposed analogy between the life of an individual and the duration of a species / Edward Forbes.

  • Forbes, Edward, 1815-1854.
Date:
1852
Catalogue details

Licence: Public Domain Mark

Credit: On the supposed analogy between the life of an individual and the duration of a species / Edward Forbes. 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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    [for the use of members.] IRopal 3n0titutton of (0rcat 'Britain* 1852. WEEKLY EVENING MEETING, Friday, May 7. W. R. Grove, Esq. M.A. F.R.S. \ ice President, in the Chair. Professor Edward Forbes, F.R.S. On the supposed Analogy between the Life of an Individual and the Duration of a Species. In Natural History and Geology a clear understanding of the rela- tions of Individual, Species, and Genus to Geological Time aird Geographical Space is of essential importance. Much, however, of what is generally received concerning these relations will scarcely hear close investigation. Among questionable, though popular no- tions upon this subject the Lecturer would place the belief that the term of duration of a species is comparable and of the same kind with that of the life of an individual. The successive phases in the complete existence of an individual are Birth, Youth, Maturity, Decline, and Decay terminating in Death. Whether we regard an individual as a single self-existing organism however produced, or extend it to the series of organisms, combined or independent, all being products of a single ovum, its term of (duration can be abbreviated but not prolonged indefinitely, nor can the several phases of its existence be repeated. Conditions may arrest or hasten maturity, or prematurely destroy, but cannot, how- ever favourable, reproduce a second maturity after decline has com- ! menced. Now, it is believed by many that a species (using the term in the I sense of an assemblage of individuals presenting certain constant :i characters in common, and derived from one original protoplast or stock) passes through a series of phases comparable with those which succeed each other in definite order during the life of a single individual, — that it has its epochs of origin, of maturity, of decline and of extinction, dependent upon the laws of an inherent vitality. If this notion be true the theory of Geology will be proportion- ' afely affected; since in this case the duration of species must be regarded as onlv influenced, not determined, by the physical condi- tions among which thev are placed;—and, thus, species should characterise epochs or sections of time, independent of all physical jehanges and modifying influences short of those which are absolutely 1 No. 13. P