Experimental Pedigree-Cultures 569 



My cultures show that quite the opposite is 

 to be regarded as fact. All organs and all quali- 

 ties 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 

 deviations around a mean, and the occurrence of 

 continuous lines of increasing deviations, link- 

 ing 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 unconnected 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 fluctua- 

 tion of the height of the Lamarckiana never de- 

 creases or even approaches that of the dwarfs. 

 There is always a gap. The smallest specimens 

 of the tall type are commonly the weakest, ac- 

 cording 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. 



