Conclusion. 501 



carefully tended. It is this fact, together with the ex- 

 clusion of the visits of insects, which are the main ad- 

 vantages of the method of cultivation. 



The experiment does not create anything new. It 

 merely enables us to see and study what happens in 

 nature. 



H: ^ 4: 



A glance at my cultures shows the mutation period 

 which I have studied to be a definite whole. It com- 

 prises a sharply circumscribed group of phenomena, 

 narrowly delimited in every respect. I mean, the same 

 events repeat themselves regularly; new ones occur but 

 seldom, and when they do, they conform to rules already 

 ascertained. We do not see a hopeless chaos of forms 

 which merge into one another; nor is the variability an 

 unlimited one. On the contrary we see a relatively small 

 number of perfectly distinct and constant forms which 

 we find appearing again and again. 



There can be little question that I have witnessed 

 neither the beginning nor the end of the period. Every- 

 thing points to the conclusion that it was in full swing 

 in the locality when I first visited it, and that the poten- 

 tiality for everything which appeared later was already 

 present there at that time. I did not see the majority of 

 the forms during the first few years probably only be- 

 cause I was not on the look-out for them. F(^r when 

 once I had got to know a form I found it every year 

 afterwards, with very few exceptions. 



It is highly improbable that I have exhausted the 

 whole wealth of latent potentialities in OcnotJicra. On 

 the contrary it is possible that even tlie most beautiful 

 and important mutations and those deviating most from 



