1865.] BRITISH ASSOCIATION. 339 



there seems to be a line which circumscribes each group, within 

 which variations occur, from food, exercise, climate, and transmit- 

 ted peculiarities. Often one specific group approaches another, or 

 several others, and a question arises whether, though now distinct, 

 or rather distinguishable, they always have been so from their be- 

 ginning, or will be always so until their disappearance. 



Whether what we call species are so many original creations 

 or derivations from a few types or one type, is discussed at length 

 in the elegant treatise of Darwin (?w), himself a naturalist of emi- 

 nent rank. It had been often discussed before. Nor will any one 

 think lightly of such enquiries, who remembers the essay of Lin- 

 naeus, ' De Telluris orbis incremento," or the investigations of 

 Brown, Prichard, Forbes, Agassiz, and.Hooker, regarding the local 

 origin of different species, genera, and families of plants and ani- 

 mals, both on the land and in the sea. Still less will he be disposed 

 to undervalue its importance, when he reflects on the many suc- 

 cessive races of living forms more or less resembling our existing 

 quadrupeds, reptiles, fishes, and mollusca, which appear to have 

 occupied definite and different parts of the depths of ancient time ; 

 as now the tiger and the jaguar, the cayman and the gavial, live 

 on different parts of the terrestrial surface. Is the living elephant 

 of Ceylon the lineal descendant of that mammoth which roamed 

 over Siberia and Europe, and North America, or of one of those 

 sub-Himalayan tribes which Dr. Falconer has made known ; or was 

 it a species dwelling only in circumpolar regions ? Can our do- 

 mestic cattle, horses and dogs, our beasts of chase and our beasts 

 of prey, be traced back to their source in older types, contempo- 

 raries of the urus, megaceros, and hyena on the plains of Europe ? 

 If so, what range of variation in structure does it indicate ? If 

 not so, by what characters are the living races separated from those 

 of earlier date ? 



Specific questions of this kind must be answered, before the 

 general proposition, that the forms of life are indefinitely variable 

 with time and circumstance, can be even examined by the light of 

 adequate evidence. That such evidence will be gathered and 

 rightly interpreted, I for one neither doubt nor fear ; nor will 

 any be too hasty in adopting extreme opinions or too fearful of 

 the final result, who remember how often that which is true has 

 been found very different from that which was plausible, and how 



(m) On the Origin of Species, 1859. 



