446 KANSAS CITY REVIEW OF SCIENCE. 



But if the geological record be imperfect, it is still very instructive. The 

 further paleontology has progressed the more it has tended to fill up the gaps be- 

 tween existing groups and species, while the careful study of living forms has 

 brought into prominence the variations dependent on food, climate, habitat, and 

 other conditions, and shown that many species long supposed to be absolutely 

 distinct are so closely linked together by intermediate forms that it is difficult to 

 draw a satisfactory line between them. Thus the European and American bisons 

 are connected by the Bison prisons of Prehistoric Europe ; the grizzly bear and 

 the brown bear, as Busk has shown, are apparently the modern representatives 

 of the cave bear ; Flower has pointed out the paleontological evidence of gradual 

 modification of animal forms in the Artiodactyles ; while among the Invertebrata, 

 Carpenter and Williamson have proved that it is almost impossible to divide the 

 Foraminifera into well-marked species ; and, lastly, among plants, there are large 

 genera, as, for instance, Rubus and Hieracium, with reference to the species of 

 which no two botanists are agreed. 



The principles of classification point also in the same direction, and are based 

 more and more on the theory of descent. Biologists endeavor to arrange animals 

 on what is called the "natural system." No one now places whales among fish, 

 bats among birds, or shrews with mice, notwithstanding their external similarity; 

 and Darwin maintained that " community of descent was the hidden bond which 

 naturalists had been unconsciously seeking." How else, indeed, can we explain 

 the fact that the framework of bones is so similar in the arm of a man, the wing of 

 a bat, the fore-leg of a horse, and the fin of a porpoise — that the neck of a giraffe 

 and that of an elephant contain the same number of vertebrae? 



Strong evidence is, moreover, afforded by embryology \ by the presence of 

 rudimentary organs and transient characters, as, for instance, the existence in 

 the calf of certain teeth which never cut the gums, the shrivelled and useless 

 wings of some beetles, the presence of a series of arteries in the embryos of the 

 higher Vertebrata exacdy 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 in- 

 numerable other facts, of the same character, appear to be incompatible 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 misunderstood. 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 De 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 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 



