96 RAMBLES OF A NATURALIST. 



of these different groups, to recognise their true 

 relations by an exact appreciation of their resem- 

 blances and differences, and to calculate to a certain 

 extent their proximity or divergence,, this is the 

 problem which modern science proposes to solve, 

 a problem of immense difficulty, towards the 

 solution of which we are undoubtedly advancing, 

 although it must be admitted that our progress is 

 effected with a tardiness necessitated by the cha- 

 racter of the inquiry. 



Many centuries will probably elapse before na- 

 turalists will acquire sufficient knowledge of animals 

 definitely to establish primary, secondary, and ter- 

 tiary groups. There are some groups, however, 

 which may be regarded as thoroughly fixed, even in 

 the present day. Whenever we study one of these 

 truly natural groups, whenever we weigh and ap- 

 preciate all its characters, we are led almost invo- 

 luntarily to conceive some ideal or virtual type 

 which might reunite these characters in the highest 

 possible degree. But there will always be a discre- 

 pancy between this type and its manifestation in 

 existing species. It is thus that Man and Woman 

 have never hitherto presented a complete realisation 

 of the beauty which painters and sculptors have 

 dreamed of, and which a few of them have imper- 

 fectly succeeded in tracing on canvass or in chisel- 

 ling from the rock. 



In all natural groups, we encounter a certain 

 number of species which present, in a high degree, 

 the characteristic impress of their type. There are 

 others, on the contrary, in which this impression 



