30 DARWINISM TO-DAY. 



discover, in the haze of the smoke of battle, of the actual 

 present state of the besieged and besiegers. 



Distinctly the most comprehensive, the fairest-minded 

 review of gegen-nnd-fiir Darwinismns in recent literature is 

 Plate's extension of his address, "Uber die Bedeutung des 

 Darwin'schen Selectionsprincips," made in Hamburg be- 

 fore the Deutsche Zoologische Gesellschaft in 1899. To 

 this review, as published in 1903 after being extended and 

 brought up to date, I beg to acknowledge a special indebted- 

 ness in my present attempt to get together the more im- 

 portant criticism, both adverse and defensive, of Darwin. 

 I have, however, assiduously sought out (with the help of 

 librarians and my indefatigable Leipzig book-dealer friend 

 Bernh. Liebisch), and perused the original pourings-forth of 

 criticism and vilification even to the reading of some matter 

 written by certain Roman Catholic priests with a consider- 

 able amateur interest in natural history and a strong pro- 

 fessional interest in anti-Darwinism ! But Plate has been 

 a guiding hand in this search for active attacks and de- 

 fence. 



The natural selection theory as an all-sufficient explanation 

 of adaptation and species-forming has always had a weak- 

 ness at its base ; it depends absolutely, of course, 

 Natural selec- on the pre-existence of variations, but it itself 



tion theory based . . 



on variation. has no influence whatever on the origin or con- 

 trol of these variations except in so far as it may 

 determine what individuals shall be permitted to give birth 

 to other individuals. Now one of the chief problems in 

 biology is exactly that of the origin, the causes, and the 

 primary control of these congenital variations. 6 Three 

 principal explanations, no one of them experimentally 

 proved or even fairly tested as yet, have been given of this 

 actually occurring congenital variation, viz., (i) that there 

 exists in the germ-plasm an inherent tendency or capacity 

 to vary so that there is inevitable variation in all individuals 



