8 ADDRESS TO THE BRITISH ASSOCIATION, 1881. 



of a series of arteries in the embryos of the higher 

 Vertebrata exactly similar to those which supply the 

 gills in fishes, even the spots on the young blackbird, 

 the stripes on the lion's cub ; these, and innumerable 

 other facts of the same character, appear to be incom- 

 patible with the idea that each species was specially and 

 independently created ; and to prove, on the contrary, 

 that the embryonic stages of species show us more or 

 less clearly the structure of their ancestors. 



Darwin's views, however, are still much misunder- 

 stood. I believe there are thousands who consider that 

 according to his theory a sheep might turn into a cow, 

 or a zebra into a horse. No one would more confidently 

 withstand any such hypothesis, his view being, of 

 course, not that the one could be changed into the 

 other, but that both are descended from a common 

 ancestor. 



No one, at any rate, will question the immense im- 

 pulse which Darwin has given to the study of natural 

 history, the number of new views he has opened up, 

 and the additional interest which he has aroused in, and 

 contributed to, Biology. When we were young we 

 knew that the leopard had spots, the tiger was striped, 

 and the lion tawny ; but why this was so it did not 

 occur to us to ask ; and if we had asked no one could 

 have answered. Now we see at a glance that the 

 stripes of the tiger have reference to its life among 

 jungle-grasses ; the lion is sandy, like the desert ; 

 while the markings of the leopard resemble spots of 

 sunshine glancing through the leaves. Again, Wallace 

 in his charming essays on natural selection has shown 

 how the same philosophy may be applied even to birds' 



