212 CONTINUITY. 



reproductions. That there was a time, and possibly may be 

 now, when inorganic matter, by infinitesimally slow changes, 

 became or becomes organised, I am far from denying. All I 

 hesitate to accept is heterogeny of self-moving reproductive 

 organisms, which seem less complex than larger vitalised 

 beings only in all probability because our microscopes are 

 not powerful enough to detect their structures.] 



The great difficulty which is met with at the threshold of 

 enquiry into the origin of species is the definition of species ; 

 in fact, species can hardly be defined without begging the 

 question in dispute. 



Thus, if species be said to be a perseverance of type inca- 

 pable of blending itself with other types, or, which comes 

 nearly to the same thing, incapable of producing by union 

 with other types offspring of an intermediate character 

 which can again reproduce, we arrive at this result, that when- 

 ever the advocate of continuity shows a blending of what had 

 been hitherto deemed separate species, the answer is, they 

 were considered separate species by mistake ; they do not now 

 come under the definition of species, because they interbreed. 



The line of demarcation is thus ex hypothesi removed a 

 step farther, so that unless the advocate of continuity can, on 

 his side, prove the whole question in dispute, by showing that 

 all can directly or by intermediate varieties reproduce, he is 

 defeated by the definition itself of species. 



On the other hand, if this, or something in fact amounting 

 to it, be not the definition of species if it be admitted that 

 distinct species can, under certain favourable conditions, pro- 

 duce intermediate offspring capable of reproduction, then 

 continuity in some mode or other is admitted. 



The question, then, takes this form : Are there species or 

 are there not ? Is the word to be used as signifying a real, 

 natural distinction, or as a mere convenient designation ap- 

 plied to subdivisions, having a permanence which will pro- 

 bably outlive man's discussions on the subject, but not an 

 absolute fixity ? The same question, in a wider sense, and 

 taking into consideration a much longer time, would be appli- 

 cable to genera and families. 



Actual experiment has done little to elucidate the ques- 



