PREFACE TO THE FIRST VOLUME. 



The origin of species has so far been the object of com- 

 parative study only. It is generally believed that this highly 

 important phenomenon does not lend itself to direct obser- 

 vation, and, much less, to experimental investigation. 



This belief has its root in the prevalent form of the con- 

 ception of species and in the opinion that the species of 

 animals and plants have originated by imperceptible grada- 

 tions. These changes are indeed believed to be so slow that 

 the life of a man is not long enough to enable him to witness 

 the origin of a new form. 



The object of the present book is to show that species 

 arise by saltations and that the individual saltations are 

 occurrences which can be observed like any other physio- 

 logical process. Forms which arise by a single saltation 

 are distinguishable from one another as sharply and in as 

 many ways as most of the so-called small species and as 

 many of the closely related species of the best systematists, 

 including Linnaeus himself. 



In this way we may hope to realize the possibility of 

 elucidating, by experiment, the laws to which the origin 

 of new species conform. The results of these studies can 

 then be compared with those which have been obtained 

 with systematic, biological and particularly with palseonto- 

 logical data. A most remarkable agreement will be found 

 to exist between these and my new results. 



These saltations, or mutations, of which the so-called 



