DARWIN AND NATURAL SELECTION 51 



terms, the orthogenetic theory may be summed up 

 in the words of Korschinsky, as quoted by Kellog : 

 " In order to explain the origin of higher forms 

 out of lower, it is necessary to assume in the organ- 

 ism a special tendency towards progress." Or, 

 again, it may be given in the words of Henslow :* 

 " The origin of Variations in Structure (upon 

 which alone species are based) is due to an inherent 

 power within the plant, by means of which it 

 responds to the direct action of changed con- 

 ditions of life." Unpalatable as it undoubtedly 

 is to biologists of the type of Weismann and Plate, 

 and in fact all the adherents of the pure material- 

 istic school, there can be no doubt that vitalistic 

 views are daily gaining ground, and that some such 

 vitalistic explanation as those just cited does fit 

 in with and explain the facts as no chemico- 

 physical theory of the day goes. Of course, it may 

 be said that such a theory can no more be demon- 

 strated by the microscope than can Weismann's 

 Biophores. But the two things are not in $ari 

 materia. Weismann's imaginary objects, if they 

 existed, would be actual particles of matter and, 

 therefore, might conceivably be demonstrated 

 by some instrument of powers at present unknown 

 to science at any rate ought to be theoretically 

 capable of ocular demonstration. Until, therefore, 

 they are demonstrated, they cannot be said to 

 have come within the cognizance of science. The 

 " entelechy," the " vital " or " bathmic force," 

 or whatever else one may care to style it the 

 inherent power is not a material object like a 



* The Heredity of Acquired Characters in Plants (1908), p. 6. 



