Though it be true that dolus latet in generalibus, it is a more important truth that “without premature generalisations the true generalisation would never be arrived at.”89 Therefore I conclude:— 1. That Plasto-diethesis, or the moulding and sifting processes experienced by organisms, represents the beginning and end of higher animal evolution; and that its wide hyphen stands for the provinces where Mendelism, Mutationism, Tetraplasty, Orthogenesis, and the dynamical work of growth on Form, as well as other factors yet to be discovered, can range at large. 2. That personal selection is the leading form of that process in higher animals, whereas among Invertebrates, especially unicellular forms, selection of groups is the rule. 3. That Initiative in animal evolution comes by stimulation, excitation, and response in new conditions, and is followed by repetition of these phenomena until they result in structural modifications, transmitted and directed by selection and the laws of genetics—a series of 4. That undesigned experiments in the arrangement of the Mammalian hair, and the production of new bursÆ, as well as the designed experiments of Pawlow, support the foregoing claims, with which agree the converging facts of—varieties of epidermis, arrangement of the papillary ridges, flexures of the palm and sole, the formation of the plantar arch, the origin of certain muscles, the innervation of the human skin, and the building of reflex-arcs. 5. That there is a large place in higher animals for the Evolution of the Indifferent through the action of use and habit. 6. That the position for Initiative in Evolution here advanced is no bar to unlimited research. |