False Atavism 191 



bility. ' ' And to avoid the repetition of the lat- 

 ter word it is called " fluctuation.^' In con- 

 trast to these fluctuations are the so-called 

 sports or single varieties, not rarely denomi- 

 nated spontaneous variations, and for which I 

 propose to use the term *^ mutations. '^ They 

 are of very rare occurrence and are to be con- 

 sidered as sudden and definite steps. 



Lastly, we have to consider those varieties, 

 which vary in a much wider range than the 

 ordinary ones, and seem to fluctuate between 

 two opposite extremes, as for instance varie- 

 gated leaves, cultivated varieties with va- 

 riegated or striped flowers, double flowers 

 and some other anomalies. They are ever- 

 sporting and ever-returning from one type to 

 the other. If however, we take the group of 

 these extremes and their intermediates as a 

 whole, this group remains constant during the 

 succeeding generations. Here we find once 

 more an instance of the seemingly contradictory 

 combination of high variability and absolute 

 constancy. It means that the range of varia- 

 bility has quite definite limits, which in the com- 

 mon course of things, are never transgressed. 



We may infer therefore that the word varia- 

 bility has such a wide range of meanings that 

 it ought never be used without explanation. 



