OTHER THEORIES OF SPECIES-FORMING. 189 



enhance the credit of selection and to discredit certain other 



species-forming theories, in particular the only one, namely, 



Lamarckism, which, until recently, has been in 



Weismann as 



champion of any real sense a rival of Darwinism. Against 

 selection. Weismann then and against Weismann's re- 



modelled kind of Darwinism, against his propaganda of the 

 Allmacht of selection, the adherents of Lamarckism and the 

 critics of selection have turned their sharpest weapons. The 

 result of the struggle has been to compel Weismann himself 

 to say : "Although the principle of selection appears to solve 

 in simplest manner the riddle of the fitness (Zweckmassig- 

 kcit) of all arising organisms (alles Entstehendcn), yet it 

 appears ever more clearly in the course of the further inves- 

 tigation of the problem, that one cannot explain all with it, 

 at least in its original limitations (dass man niit ihm, in 

 seiner ursprilngliche Beschrankung, wenigstens, nicht 

 ausreicht)" 



To support the selection theory in two of its w r eakest and 

 most criticised places, Weismann has proposed two striking 

 auxiliary theories, namely, the Theory of Panmixia, to 

 explain the degeneration of functions and organs, and the 

 more recent Theory of Germinal Selection, to account 

 for the now practically generally admitted existence of 

 orthogenesis or determinate variation and evolutionary 

 progress along fixed lines even to the possible final dis- 

 advantage of the organisms involved, and to account for 

 the beginnings of variation and their maintenance until 

 sufficiently developed to serve as handles for selection. The 

 proposal by Weismann of the second theory, that of 

 germinal selection, was the practical admission on his part 

 of the impotence of selection to initiate new lines of develop- 

 ment or descent. It was a concession on Weismann's part 

 of the justness of the demand for an evolutionary factor to 

 explain the beginnings of lines of development, whether of 

 new organs or new species. And there is no doubt that it is 



