ADDRESS. 5 



was specially and independently created; and to prove, on the conLuiy, 

 that the embryonic stages of species show us more or less clearly the 

 structure of their ancestors. 



Darwin's views, however, are still much misunderstood. I believe 

 there are thousands who consider that according to his theory a sheep 

 mio'ht turn into a cow, or a zebra into a horse. No one would more 

 confidently withstand any such hypothesis, his view benig, 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 impulse which Darwin 

 has given to the study of natural history, the number of new views 

 he has opened np, 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 sti-iped, and the lion tawny ; but why 

 this was so it did not occur to us to ask ; and if we had asked no one 

 would 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' nests— how, for instance, open nests have led to the 

 dull color of hen birds ; the only British exception being the kingfisher, 

 which, as we know, nests in river-banks. Lower still, among insects, 

 Weismann has taught us that even the markings of caterpillars are full of 

 interesting lessons ; while, 'in other cases, specially among butterfliei?, 

 Bates has made known to us the curious phenomena of mimicry. 



The science of embryology may almost be said to have been created in 

 the last half-century. Fifty years ago it was a very general opinion that 

 animals which are unlike when mature, were dissimilar from the begin- 

 ning. It is to Von Baer, the discoverer of the mammalian ovum, that we 

 owe the great generalisation that the development of the egg is in the 

 main a progress from the general to the special, that zoological affinity is 

 the expression of similarity of development, and that the different great 

 types of animal structure are the result of different modes of develop- 

 ment — in fact, that embryology is the key to the laws of animal develop- 

 ment. 



Thus the young of existing species resemble in many cases the mature 

 forms which flourished in ancient times. Huxley has traced np the 

 genealogy of the horse to the Miocene Anchitherium, and his views have 

 since been remarkably confirmed by Marsh's discovery of the Pliohippus, 

 Protohippus, Miohipims, and Mesohippus, leading down from the Eohippua 

 of the early tertiary strata. In the same way Boyd-Dawkins has called 

 attention to the fact that just as the individual stag gradually acquires more 

 and more complex antlers : having at first only a single prong, in the next 

 year two points, in the following three, and so on ; so the genus, as a 

 whole, in Middle Miocene times, had two pronged horns ; in the Upper 



