MUTATION 319 



difficulties of the followers of Darwin. The ma- 

 jority assumed that species arise by the slow accumu- 

 lation of slight fluctuating deviations, and the muta- 

 tions were only to be considered as extreme 

 fluctuations, obtained, in the main, by a continuous 

 selection of small differences in a constant direction." 



"My cultures show that quite the opposite is to be 

 regarded as fact. All organs and all qualities of 

 lamarchiana fluctuate and vary in a more or less evi- 

 dent manner, and those which I had the opportunity 

 of examining more closely were found to comply 

 with the general laws of fluctuation. But such oscil- 

 lating changes have nothing in common with the mu- 

 tations. Their essential character is the heaping up 

 of slight deviations around a mean, and the occur- 

 rence of continuous lines of increasing deviations, 

 linking 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 ex- 

 treme only is to be seen, and it is wholly unconnected 

 with the original tj^pe. The offspring of my mu- 

 tants are, of course, subject to the general laws of 

 fluctuating variability. They vary, however, around 

 their own mean, and this mean is simply the type of 

 the new elementary species." 



"VII. The mutations take place in nearly all di- 

 rections. They do go, according to Darwin's view, 

 in all directions, or at least in many. If these in- 



