On the Origin of Sjjecies, 109 



about the year 1600 ; never less than 20,000 pigeons were taken 

 with the court. " The inonarchs of Iran aad Turan sent him 

 some very rare birds ;" and, continues the courtly historian, '' His 

 Majesty, by crossing the breeds, which method was never prac- 

 tised before, has improved them astonishingly." About this same 

 period the Dutch were as eager about pigeons as were the old 

 Romans. The paramount importance of these considerations in 

 explaining the immense amount of variation which pigeons have 

 undergone, will be obvious when we treat of Selection. "We shall 

 then, also, see how it is that the breeds so often have a somewhat 

 monstrous character. It is also a most favourable circumstance 

 for the production of distinct breeds, that male and female pigeons 

 can be easily mated for life ; and thus different breeds can be 

 kept together in the same aviary." 



The common rock-pigeon is thus proved to be highly variable 

 in a state of domestication, so much so that naturalists not aware 

 of all the facts, might well be excused for concluding, as some of 

 them have done in the similar instances of the ox, the domestic 

 fowl, and man himself, that the varieties represent several distinct 

 species. To what then do these diflerences amount ? (1) They 

 are mainly in non-essential points, as colour, development o^ 

 feather, etc., and they do not consequently interfere, to any impor- 

 tant extent, with the food and habits of the animal ; or if we 

 were to represent the matter from the opposite point of view to 

 that taken by Mr. Darwin, the constitution and instincts of the 

 species being fixed by the law of its creation, it cannot vary be- 

 yond these. The author is clearly wrong in stating that any of 

 them could amount to generic distinctions; that is, if genera are 

 to be based on structural differences, for of these there is compa- 

 ratively little, except in the one point of proportion of parts, difter- 

 ence in which is of specific value only, and often occurs in near 

 varieties. (2) Many of the differences are abnormal ; that is, 

 they are of the character of monstrosities, and this separates them 

 widely from true specific diflerences. (3) The varieties are per- 

 fectly fertile, which is not the case with hybrids between clearly 

 distinct species. (4) The cross breeds revert to the characters 

 of the rock-pigeon, showing that the specific type still remains 

 uneradicated, or that each variety is, so to speak, a hemitropic 

 form, which, when united with an opposite one, tends to reproduce 

 the original form. It follows from these results, that, however 



