Forbes defined and advocated what he called the law of representation. He found that in all parts of the world, however far removed, and however completely separated by natural barriers, where the conditions of life are similar, species and groups of species occur which, although not identical, resemble one another very closely; and he found that this similarity existed likewise between groups of fossil remains, and between groups of fossils and groups of recent forms. Admitting the constancy of specific characters, these resemblances could not be accounted for by community of descent, and he thus arrived at the generalization, that in localities placed under similar circumstances, similar though specifically distinct specific forms were created. These he regarded as mutually representative species.
Our acceptance of the doctrines of specific centres and of representation, or, at all events, the form in which we may be inclined to accept these, depends greatly upon the acceptance or rejection of the fundamental dogma of the immutability of species; and on this point there has been a very great change of opinion within the last ten or twelve years, a change certainly due to the remarkable ability and candour with which the question has been discussed by Mr. Darwin[1] and Mr. Wallace,[2] and to the genius of Pro-
- ↑ The Origin of Species by means of Natural Selection; or, the Preservation of Favoured Races in the Struggle for Life. By Charles Darwin, M.A., F.R.S., L.S., G.S., &c. &c. London, 1859, and subsequent editions.
- ↑ Contributions to the Theory of Natural Selection. A Series of Essays by Alfred Russel Wallace. London, 1870.
