240 Darwin, and after Darwin. 



the form which presents them is not ranked as a 

 species, but as a constant variety. In other words, 

 when definitions 3 and 4 are found to clash, it is not 

 4, but 3, that is followed. In short, even up to the 

 present time, systematic naturalists play fast and 

 loose with the criterion of Heredity to such an 

 extent, that, as above observed, it has been rendered 

 well nigh worthless in fact, whatever may be thought 

 of it in theory. 



Now, unless all this can be denied, what is the 

 use of representing that a species is distinguished 

 from a variety "climatic" or otherwise by the 

 fact that its constituent individuals " reproduce their 

 like"? We are not here engaged on any abstract 

 question of what might have been the best principles 

 of specific distinction for naturalists to have adopted. 

 We are engaged on the practical question of the 

 principles which they actually have adopted. And 

 of these principles the reproduction of like by like, 

 under all circumstances of environment, has been 

 virtually ignored. 



(B.) 



In the second place, supposing that the criterion 

 of Heredity had been as universally and as rigidly 

 employed by our systematists in their work of con- 

 structing species as it has been but occasionally and 

 loosely employed, could it be said that even then a basis 

 would have been furnished for the doctrine that all spe- 

 cific characters must necessarily be useful characters? 

 Obviously not, and for the following reasons. 



It is admitted that climatic characters are not 

 necessarily or even generally useful characters. 



