138 THE THEORY OF MUTATION 



formation of the pollen was very defective. None of 

 the others was lacking in either of these respects. Each 

 new form was distinguished by certain definite features 

 which affected almost all its parts, not by one new 

 character only ; and these features were never separable, 

 but always appeared in common on the same plant. 



The new species, of course, showed normal fluctuat- 

 ing variability, and, as an extreme result of this varia- 

 bility, forms occasionally appeared midway between 

 one of the new species and the parental type. In such 

 cases, when the self-fertilized seed of the plant showing 

 such an intermediate character was sown, the offspring 

 were found to group themselves round the normal 

 form of the new species or round that of the parent 

 Lamarkiana, thus affording evidence as to the true 

 nature of their parent. 



Whether or not we are prepared to accept the whole 

 of de Vries' conclusions from his experiments, we can 

 see at least that from one point of view they are of the 

 very greatest importance. For before de Vries pub- 

 lished this work it had been supposed to be quite im- 

 possible to make direct observations upon the manner 

 of origin of new species in Nature. De Vries has now 

 shown that such observations can be made, and this 

 is in itself a most valuable piece of information. He 

 has introduced an entirely new method into the domain 

 of species research, and one by the use of which it is 

 to be hoped that before long a definite answer will be 

 obtained to the question whether species in general 

 arise by definite steps, or with an imperceptible degree 

 of slowness. 



