140 MR. Darwin's work and 



Order, Primates ; and if there were any animals more 

 like men than they were like any of the apes, and yet 

 different from men in important and constant particu- 

 lars of their organization, we should rank them as 

 members of the same Family, or of the same Genus, 

 but as of distinct Species. 



That it is possible to arrange all the varied forms of 

 animals into groups, having this sort of singular subor- 

 dination one to the other, is a very remarkable circum- 

 stance ; but, as Mr. Darwin remarks, this is a result 

 which is quite to be expected, if the principles which he 

 lays down be correct. Take the case of the races which 

 are known to be produced by the operation of atavism 

 and variability, and the conditions of existence which 

 check and modify these tendencies. Take the case of the 

 pigeons that I brought before you : there it was shown 

 that they might be all classed as belonging to some one 

 of five principal divisions, and that within these divisions 

 other subordinate groups might be formed. The mem- 

 bers of these groups are related to one another in just 

 the same way as the genera of a family, and the groups 

 themselves as the families of an order, or the orders of 

 a class ; while all have the same sort of structural rela- 

 tions with the wild Rock-pigeon, as the members of any 

 great natural group have with a real or imaginary 

 typical form. Now, we know that all varieties of 

 pigeons of every kind have arisen by a process of 

 selective breeding from a common stock, the Rock- 

 pigeon ; hence, you see, that if all species of animals 

 have proceeded from some common stock, the general 

 character of their structural relations, and of our sys- 

 tems of classification, which express those relations, 



