54 'WHAT IS A SPECIES?* 



Instances will he drawn from the Le})lc]optera rather 

 than other Orders of insects, because of the nuniherless 

 examples ot subtle distinction between forms which but 

 yesterday, so to speak, became separate ; because of our 

 knowledije, insufficient but considerable, of their ijco- 

 C^raphical rani^e ; because of our exj)erience, excessively 

 imi>erfect and scanty, but still much larger than in other 

 Orders, of interbreeding and of descent from parent to 

 offspring. 



The LinnacaJi Coiccption of Species as Separately Created, 

 and Fixed for all time at their Creation. 



First among the attempts to define species must be 

 placed that which we rightly associate with the name of 

 Linnaeus : — ' Species tot sunt, quot diversas formas ab 

 initio j)roduxit Infinitum Ens, quae formae, secundum 

 gcnerationis inditas leges produxere plures, at sibi semper 

 similes.' 



ll is necessar)- at the outset to point out that the 

 Linnaean definition contains two widely different ideas. 



First, species are diver sac formae, distinguished from 

 one another b)' characters which can be studied and de- 

 fined. Secondl}', these specific differences were originally 

 created as we see them, and are for ever permanent and 

 fixed. 



I ])ropose to discuss the second idea before the first. 



It has been admirably j)ointed out by the late Rev. 

 Aubrey L. Moore, ^ that the dogma of the fixity of 

 species is entitled to none of the respect which is due to 

 ai^e. * It is hardh" credible to us,' he wrote, * that Lord 

 Inicon, "the father of modern science" as he is called, 

 though he was only a schoolman touched with cmi)iricism, 

 believed not only that one species might i)ass into 

 another, but that it was a matter of chance what the 

 transmutation would be. Sometimes the mediaeval 

 nolion of vivification from putrefaction is appealed to, as 

 where he explains the reason why oak boughs put into 

 the earth send forth wild vines, " which, if it be true (no 



* Science and the Faith ^ London, 1889, pp. 174 et seq. 



