SECTION I 



THE NEWEST THEORIES CONCERNING EVOLUTION 



Before I proceed to the exposition of my own views I must 

 briefly discuss some of those attempts to explain the evolution 

 of organisms which have been made by others in recent years, 

 namely, those of Weismann and Nageli. 



The theory of heredity introduced by AVeismann under 

 the name " Continuity of the Germ-plasm,"^ has recently been 

 widely discussed, partly in a favourable, partly in an adverse 

 spirit.^ 



This theory seeks to explain the fact that the characters 

 of the parents are inherited to so high a degree by the 

 children, and the other fact that characters can be inherited 

 from more remote ancestors, e.g. from the grandparents, 



^ A. Weismann, Die Kontinuitdt cles Keimplasvm als Grundlage einer 

 Theorie der Vererhung, Jena, G. Fischer, 1885. The same : Z\tr Frage 7iach 

 der Vererhung ei-worhener Eigenschaften, Biolog. Centralhlatty 1886, Bd. vi. 

 No. 2. 



- E.g. Naturforscher, 1886, No. 1. Eimer, Deidscher LitteraturzeiUmg 

 15th May 1886. V. v. Ebner, Ueher Vererhung, Lecture delivered to the So 

 ciety of Physicians of Steiermark, 22d March 1886 {Betz MemoraJjilien, 2 Heft 

 1886). Kulliker, Die Bedexdung der Zellkerne fur die Vorgilnge der Vererhung 

 Zeitsch.f. V). Zool. 1885 ; and Dcts Karyoplasnui und die Vererhung, eine Kritik 

 der Weisma/ans' clien Theorie von der Kontinuitdt des Keim]jlasnia, ihid. 1886 

 Virchdw, Descendenz und Pathologie, Arch. f. patholog. Anat. Bd. ciii. Koll 

 mann, Biolog. Centralhlatt, Bd. v. 1886. Virchow, Verhandlungen der Strass 

 burger Naturforscherversammlung, 1885, Address delivered at the second general 

 meeting of this Congress. 



