118 THE DARWINIAN HYPOTHESIS 



sion for alarms if a highly advanced knowledge, like that 

 of the eminent Naturalist before us, confronts us with an 

 hypothesis as vast as it is novel. This hypothesis may or 

 may not be sustainable hereafter ; it may give way to 

 something else, and higher science may reverse what science 

 has here built up with so much skill and patience, but its 

 sufficiency must be tried by the tests of science alone, if 

 we are to maintain our position as the heirs of Bacon and 

 the acquitters of Galileo. We must weigh this hypothesis 

 strictly in the controversy which is coming, by the only 

 tests which are appropriate, and by no others whatsoever. 

 The hypothesis to which we point, and of which the 

 present work of Mr. Darwin is but the preliminary outline, 

 may be stated in his own language as follows : " Species 

 originated by means of natural selection, or through the 

 preservation of the favoured races in the struggle for life." To 

 render this thesis intelligible, it is necessary to interpret its 

 terms. In the first place, what is a species ? The question 

 is a simple one, but the right answer to it is hard to find, 

 even if we appeal to those who should know most about it. 

 It is all those animals or plants which have descended 

 from a single pah* of parents ; it is the smallest distinctly 

 definable group of living organisms ; it is an eternal and 

 immutable entity ; it is a mere abstraction of the human 

 intellect having no existence in nature. Such are a few 

 of the significations attached to this simple word which 

 may be culled from authoritative sources ; and if, leaving 

 terms and theoretical subtleties aside, we turn to facts 

 and endeavour to gather a meaning for ourselves, by study- 

 ing the things to which, in practice, the name of species is 

 applied, it profits us little. For practice varies as much 

 as theory. Let the botanist or the zoologist examine and 

 describe the productions of a country, and one will pretty 

 certainly disagree with the other as to the number, limits, 

 and definitions of the species into which he groups the very 

 same things. In these islands we are in the habit of 

 regarding mankind as of one species, but a fortnight's steam 

 will land us in a country where divines and savans, for once 

 in agreement, vie with one another in loudncss of assertion, 

 if not in cogency of proof, that men arc of different species ; 

 and, more particularly, that the species negro is so distinct 

 from our own that the Ten Commandments have actually 

 no reference to him. Even in the calm region of entomol- 

 ogy, where, if anywhere in this sinful world, passion and 



