20 CHAPTERS ON EVOLUTION, 



living beings, we are able as a consequence to place together those 

 which are truly alike, and to separate those which are unlike. 



By way of illustrating the application of morphology, and on the 

 principle that example is better than precept, let us select as an 

 example of scientific inquiry the history of a fish. Under the head 

 of morphology, the biologist is bound to take account of every 

 detail of structure which that animal exhibits. Through the aid of 

 " anatomy " he will make its acquaintance as a fully formed being ; 

 he will ascertain the full details of its structure ; note the form, 

 number, position, and relation of its organs; and in general obtain a 

 thorough knowledge of its composition and bodily mechanism. 

 But anatomy does not inform him of the prior history of the fish ; 

 hence he turns to development as a means of showing him the 

 manner in which the fish-body grew and was fashioned. Beginning 

 as a small speck of protoplasm, indistinguishable from the matter 

 1 which forms the whole body of the lower animalcule, he would trace 

 for us the evolution of the complex body from materials of extreme 

 simplicity. Hour by hour, and day by day, he would chronicle the 

 changes in the division of the egg, the first appearance of the 

 embryo, the beginnings of the heart-pulse, the formation of brain and 

 nerve, and the outlining of body at large. And, finally, he would 

 show how the completed being, evolved by strange artifice from 

 literal nothingness, grows to its adult form and takes its place 

 amongst the finished products of nature. Such are the details of 

 development. 



Finally, asking himself concerning the place and rank of the fish 

 in the scale of creation, the biologist would turn to " classification " 

 to aid him in his search. Ascertaining the structure and develop- 

 ment of other fishes, he would know accurately enough the proper 

 sphere to which science calls, and in which science places, the form 

 before him. He would find cause to utterly reject classifications 

 and systems of arrangement not founded upon a true knowledge of 

 structure. The whale, for instance, is classified as a fish by primi- 

 tive man and, I may add, also by persons amongst ourselves, whose 

 culture professes to be by no means of a low grade. It is fish-like 

 in form and appearance ; it inhabits the sea ; its conditions of life 

 are evidently those of the fish. Why, then, asks popular opinion, is 

 the whale not a fish, seeing that in any case the latter is " very like 

 a whale " ? To this question the biologist can but reply, that if 

 nature has modelled whale and fish on the same lines, he can have 

 no quarrel with nature on that account. His, however, is the duty 

 to assure himself that the fish and whale are really alike. Through 

 anatomy he learns that, outwardly alike as the two animals are, 

 things in this instance are really not what they seem. The fish, his 

 study of morphology informs him, has cold blood, and a heart con- 



