202 DARWINIANA. 



equally have to be verified inferentially. If we still 

 hold to the idea of Linn reus, and of Agassiz, that ex- 

 isting species were created independently and essen- 

 tially all at once at the beginning of the present era, 

 we could not better the propositions of Linnaeus and 

 of Jussieu. If, on the other hand, the time has come 

 in which we may accept, with De Candolle, their suc- 

 cessive origination, at the commencement of the pres- 

 ent era or before, and even by derivation from other 

 forms, then the " in principle)" of Linnaeus will refer 

 to that time, whenever it was, and his proposition be 

 as sound and wise as ever. 



In his " Geographie Botanique " (ii., 1068-1077) De 

 Candolle discusses this subject at length, and in the 

 same interest. Remarking that of the two great facts 

 of species, viz., likeness among the individuals, and 

 genealogical connection, zoologists have generally pre- 

 ferred the latter, 1 while botanists have been divided in 

 opinion, he pronounces for the former as the essen- 

 tial thing, in the following argumentative statement : 



" Quant a moi, j'ai 6te conduit, dans ma definition de l'espece, 

 a mettre decidement la ressemblance au-dessus de caracteres de 

 succession. Ce n'est pas seulement a cause des circonstances 

 propres au regne vegetal, dont je m'occupe exclusivement ; ce 

 n'est pas non plus afin de sortir ma definition des theories et de 

 la rendre le plus possible utile aux naturalistes descripteurs et 

 nomenclateurs, e'est aussi par un motif philosophique. En toute 

 chose il f aut aller au fond des questions, quand on le peut. Or, 

 pourquoi la reproduction est-elle possible, habituelle, feconde 

 indefiniment, entre des etres organises que nous dirons de la 



1 Particularly citing Flourens : " La ressemblance n'est qu'une con- 

 dition secondaire ; la condition essentielle est la descendance : ce n'est 

 pas la ressemblance, e'est la succession des individus, qui fait l'espece." 



