xxxvi Contents. 



I. 



Are the Principles of the Selection Theory Mechanical ? 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 charac- 

 ters appearing singly may also acquire predominance, 659. A mecha- 

 nical theory of heredity is as yet wanting, 665. HaeckePs " 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 selec- 

 tion are thus mechanical, 675. Importance of the physical constitu- 

 tion 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 phy- 

 letic vital force, 687. The two are inseparable, 690. 



II. 



Mechanism and Teleology ', p. 694. 



Von Baer's exaction from the theory of selection, 694. Justifica- 

 tion 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 meta- 

 physical (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 Mate- 

 rialism, 716. 



INDEX p. 719. 



