Part III On the Final Causes of Transformation (Continued)
The Transformation of the Mexican Axolotl Into Amblystoma
Introduction, p. 555.
Experiments, 558. Significance of the facts, 563. The Axolotl rarely or never undergoes metamorphosis in its native country, 565. North American Amblystomas, 570. Does the exceptional transformation depend upon a phyletic advancement of the species? 571. Theoretical bearing of the case, 574. Differences between Axolotl and Amblystoma, 575. These are not correlative results of the suppression of the gills, 578. Explanation by reversion, 581. Cases of degeneration to a lower phyletic stage: Filippi’s sexually mature “Triton larvæ,” 583. Analogous observations on Triton by Jullien and Schreibers, 591. The sterility of the artificially produced Amblystomas tells against the former importance of the transformation, 594. It is not opposed to the hypothesis of reversion, 596. Attempted explanation of the sterility from this point of view, 597. Causes which may have induced reversion in the hypothetical Mexican Amblystomas, 600. Saltness of the water combined with the drying up of the shores by winds, 604. Consequences of the reversion hypothesis, 609; Systematic, 609; an addendum to the “fundamental biogenetic law,” 611; General importance of reversion, 612. Postscript; dryness of the air the probable cause of the assumed reversion of the Amblystoma to the Axolotl, 613. Addendum, 622.
IV.
ON THE MECHANICAL CONCEPTION OF NATURE.
Introduction, p. 634.
Results of the three foregoing essays: denial of a phyletic vital force, 634. Application of these results to inductive conclusions with reference to the organic world in general, 636. The assumption of such a force is opposed to the fundamental laws of natural science, 637. The “vital force” of the older natural philosopher, 640. Why was the latter abandoned? Commencement of a mechanical theory of life, 642.
I.
Are the Principles of the Selection Theory Mechanical? p. 645.
Refutation of Von Hartmann’s views, 645. Variability, 646. The assumption of unlimited variability no postulate of the selection theory, 647. The acknowledgment of a fixed and directed variability does not necessitate the assumption of a phyletic vital force, 647. Heredity, 657. Useful modifications do not occur only singly, 657. New characters appearing singly may also acquire predominance, 659. A mechanical theory of heredity is as yet wanting, 665. Haeckel’s “Perigenesis of the Plastidule,” 667. Correlation, 670. The “specific type” depends upon the physiological equilibrium of the parts of the organism, 671. The theoretical principles of the doctrine of selection are thus mechanical, 675. Importance of the physical constitution of the organism in determining the quality of variations, 676. All individual variability depends upon unequal external influences, 677. Deduction of the limitability of variation, 682. Deduction of local forms, 686. Parallelism between the ontogenetic and the phyletic vital force, 687. The two are inseparable, 690.
II.
Mechanism and Teleology, p. 694.
Von Baer’s exaction from the theory of selection, 694. Justification of his claim, but the impossibility of the co-operation of a metaphysical principle with the mechanism of Nature, 695. Per saltum development (heterogeneous generation), 698. Weakness of the positive basis of this hypothesis, 699. The latter refuted by the impossibility of the co-operation of “heterogeneous generation” with natural selection, 702. The interruption by a metaphysical principle cannot be reconciled with gradual transformation, 705. The metaphysical (teleological) principle can only be conceived of as the ultimate ground of the mechanism of Nature, 709. Value of this knowledge for the harmonious conception of the Universe, 711. Explanation of the spiritual by the assumption of conscious matter, 714. The theory of selection does not necessarily lead to Materialism, 716.
Index p. 719.