28 DARWINISM TO-DAY. 



at the same time a curious paucity of satisfactory or at all 

 convincing substitutionary theory offered by the anti- 

 Darwinians to replace that which they are attempting to 

 dethrone. The situation illustrates -admirably the varying 

 worth of a few facts. A few stubborn facts of the wrong 

 complexion are fatal things for a theory ; they are immensely 

 effective offensive weapons. But these same few facts make 

 a pitiable showing when they are called on to support a 

 theory of their own. It was exactly the greatest part of 

 Darwin's greatness, it seems to me, that he launched his 

 theory only after making the most remarkable collection of 

 facts yet gathered together in biological science by any one 

 man. Testing his theory by applying to it successively 

 fact after fact, group after group and category after category 

 of facts, he convinced himself of the theory's consonance 

 with all this vast array of observed biological actuality. 

 Compare the grounding of any of the now offered replacing" 

 theories with the preparation and founding of Darwinism. 

 In_j864 von JKolJiker/ a great biologist, convinced of the 

 incapacity of natural selection to do the work assigned it by 

 its founders and friends, suggested a theory of the origin of 

 species by considerable leaps; in 1899, Korschinsky, 3 on the 

 basis of sorneiew personal observations and the compiling 

 of some others, definitely formulated a theory of species- 

 forming by sudden considerable variations, namely, muta- 

 tions ; in 1901 and 1903 appeared the two volumes of de 

 Vries's "Die Mutationstheorie," in which are revealed the 

 results of long years of careful personal observation, in 

 truly Darwinian manner, directed toward the testing and 

 better grounding of this mutationstheorie of species-origin. 

 The results are : out of many plant species studied, a few 

 show at certain times in the course of numerous generations 

 a behaviour in accordance with the demands of a theory 

 of species-forming by sudden definitive modification; that 

 is, species-forming by mutations. The mutations-theory 



