CHAPTER I. 

 DEFINITIONS OF TERMS USED. 



The evolution of living beings is, as follows directly 

 from what has been said in the introduction, but part 

 of the general problem of Evolution, and again the 

 Origin of species is but part of the more general pro- 

 blem of the origin of all those differently constituted 

 Types which people the globe. 



Why, we shall see bye and bye. 



For the present we will limit our remarks to the ori- 

 gin of species, and more especially to the origin of 

 those species which we now designate as the diploid 

 ones, e. g. which belong to the class which embraces 

 all so called higher beings. 



He who ventures to write on the origin of species, 

 ought to define what a species is, so ought he to do 

 who describes species, no matter whether he considers 

 his task finished when the description has been made, 

 or whether he intends to make use of the described 

 species to build up a more or less elaborate system. 

 In other words : the systematist, as well as the evoluti- 

 onist, ought to state clearly what he means by a spe- 

 cies. 



As a matter of fact neither of them usually does. 



In 1855 Alphonse DE CANDOLLE said already in his 

 Geographic botanique raisonnee (T. II. p. 1068) : 



Enoncer clairement ses opinions sur la nature de I'es- 



