A NEW THEOKY OF THE OKIGIN OF SPECIES. 511 



processes of variation, will perpetuate itself as long as these external 

 conditions are kept up. For example, in attributing the elongation of 

 the neck of a girati'e to the habit of browsing upon the high leaves of 

 trees and the effort of the animal to reach those which are still higher, 

 Lamarck accounts for the detinite and sustained course of variation. 

 But it is exactly this resource that Darwin took away, since he did not 

 accept the ideas of his illustrious predecessor as to the causes of varia- 

 tion. Decidedly, selection appears to be a process more adapted for 

 preserving a state of things than for creating a new one. It is more 

 conservative than revolutionary. 



Besides, this is not the only objection, not even the most serious 

 one, which affects this third hypothesis of Darwin. The principal 

 difficult}" with it is that it attempts to account for the considerable 

 change which creates a new species by too slow an accumulation of 

 inappreciable changes. When the Darwinists are pressed closely they 

 demand time — much time; too much time. The}" require indefinite 

 series of generation's in order that the smallest species may be formed. 

 Their adversaries have reproached them with having made our globe 

 too old; this is also the opinion of Lord Kelvin. 



In reality it must be that there is not so much delay in the creation 

 of a new species. This is exactly what Hugo de Vries contends. He 

 denies the gradual transformation of species by the addition of inap- 

 preciable variations; or, at least, he affirms that they may be produced 

 by a process that is rapid, precipitate, sudden. The new species 

 wdiose development he has observed have arisen abruptly, as one nn.y 

 say, explosively. This is what the Dutch naturalist calls " spasmodic 

 progress." 



II. 



The main idea of the doctrine of Hugo de Vries is the abrupt muta- 

 tion of living forms. The eminent naturalist does not advance it as an 

 a priori proposition; he deduces it from his experiments, and he is 

 not afraid of sharply opposing it to the universal view which accepts 

 slowly acting causes. In the course of the nineteenth century, geology 

 was tossed from the cataclysms of Cuvier and his geological revolutions 

 to the slow causes of gradual (^volution pointed out by Sir Charles 

 Lyell; and at the present time it is swinging ))ack with Suess toward 

 sudden transformations. It is interesting to note that a similar move- 

 ment is occurring in ]>i()logy: the attempt of de Vries is one of its 

 manifestations. 



A great number of zoologists, ])otanists, and paleontologists are 

 inclined to adopt this notion of sudden changes as consonant with the 

 teachings of experience. We may cite in this connection the well- 

 known argument of Agassiz. This celebrated naturalist called atten- 

 tion to the siinultaneous appearance, in the first fossiliferous strata. 



