78 GENETICS AND EUGENICS 



The giant mutant was obtained only once, but all the 

 others in at least three different generations, from Lamarcki- 

 ana parents. 



Without going into the details of the case, to which De 

 Vries has devoted an entire volume, we may notice what de- 

 ductions or " laws " De Vries bases upon it. 



1. New elementary species appear suddenly and attain full constancy at 

 once. 



2. The same new species are produced in a large number of individuals. 



This would, of course, give them a better chance and fuller 

 test in the struggle for existence than if they appeared but 

 once. 



3. Mutahility is something fundamentally different from fluctuating vari- 

 ability. All organs and all qualities of Lamarckiana fluctuate and vary 

 in a more or less evident manner, and those which I had the opportunity of 

 examining more closely were found to comply with the general laws of 

 fluctuation. But such oscillating changes have nothing in common with 

 the mutations. Their essential character is the heaping up of slight devia- 

 tions around a mean, and the occurrence of continuous lines of increasing 

 deviations, Hnking the extremes with this group. Nothing of the kind is 

 observed in the case of mutations. There is no mean for them to be 

 grouped around and the extreme only is to be seen, and it is wholly un- 

 connected with the original type. It might be supposed that on closer 

 inspection each mutation might be brought into connection with some 

 feature of the fluctuating variability. But this is not the case. The dwarfs 

 are not at all the extreme variants of structure, as the fluctuation of the 

 height of the Lamarckiana never decreases or even approaches that of the 

 dwarfs. There is always a gap. The smallest specimens of the tall type 

 are commonly the weakest, according to the general rule of the relationship 

 between nourishment and variation, but the dwarfs according to this same 

 rule are of course the most robust specimens of their group. 



