436 THE ORIGIN OF SPECIES 



being, how far more interesting — I speak from experience — does 

 the study of natural history become! 



A grand and almost untrodden field of inquiry will be opened, 

 on the causes and laws of variation, on correlation, on the effects 

 of use and disuse, on the direct action of external conditions, and 

 so forth. The study of domestic productions will rise immensely 

 in value. A new variety raised by man will be a more important 

 and interesting subject for study than one more species added to 

 the infinitude of already recorded species. Our classifications will 

 come to be, as far as they can be so made, genealogies; and will 

 then truly give what may be called the plan of creation. The 

 rules for classifying will no doubt become simpler when we have 

 a definite object in view. We possess no pedigree or armorial bear- 

 ings; and we have to discover and trace the many diverging lines 

 of descent in our natural genealogies, by characters of any kind 

 which have long been inherited. Rudimentary organs will speak 

 infallibly with respect to the nature of long-lost structures. Spe- 

 cies and groups of species which are called aberrant, and which 

 may fancifully be called living fossils, will aid us in forming a 

 picture of the ancient forms of life. Embryology will often reveal 

 to us the structure, in some degree obscured, of the prototypes 

 of each great class. 



When we can feel assured that all the individuals of the same 

 species, and all the closely aUied species of most genera, have, 

 within a not very remote period, descended from one parent, and 

 have migrated from some one birthplace; and when we better 

 know the many means of migration, then, by the light which 

 geology now throws, and will continue to throw, on former 

 changes of climate and of the level of the land, we shall surely 

 be enabled to trace in an admirable manner the former migra- 

 tions of the inhabitants of the whole world. Even at present, by 

 comparing the differences between the inhabitants of the sea on 

 the opposite sides of a continent, and the nature of the various in- 

 habitants on that continent in relation to their apparent means of 

 immigration, some light can be thrown on ancient geography. 



The noble science of geology loses glory from the extreme im- 

 perfection of the record. The crust of the earth, with its em- 

 bedded remains, must not be looked at as a well-filled museum, 

 but as a poor collection made at hazard and at rare intervals. 

 The accumulation of each great fossiliferous formation will be 

 recognized as having depended on an unusual occurrence of favor- 

 able circumstances, and the blank intervals between the successive 

 stages as having been of vast duration. But we shall be able to 



