368 THE POPULAR SCIENCE MONTHLY 



see what influence zoology had on Darwin and his contemporaries. I 

 shall not try your patience by attempting to review the history of the 

 subject, but it would not belittle the greatness of Darwin's achievement 

 one whit to find that brilliant discoveries had been made before his 

 time, the theory of evolution plainly enunciated, the doctrine of spon- 

 taneous generation disproved ; comparative anatomy widely studied ; the 

 important functions of the body elucidated, the foundations of the 

 science of embryology laid, and the principles of pedigree breeding 

 followed. 



In the eighteenth century, when the study of different kinds of ani- 

 mals inhabiting sea and land attracted the attention of zoologists, great 

 classifications were invented. Two main facts emerged. On the 

 assumption of fixity of type, a classification of the different forms of 

 animals and plants became possible. But on the other hand the more 

 extensive the material to be classified, the more difficult it became to 

 make such systems, for the fixity of type was often lost in apparent 

 transitions to other types. Counter claims arose as to the superiority 

 of one system over another, and the question of an artificial system 

 versus a natural one was widely debated. Now, an artificial system, 

 like the arrangement of the words in a dictionary, is obviously only a 

 matter of convenience, but it became a question of deep philosophical 

 importance to decide what was meant by a natural classification. To 

 us at the present time a natural classification implies a relation due 

 to descent; it is neither more nor less than the natural relation of a 

 man to his ancestors. But it were a fatal mistake to read our meaning 

 backwards to the time before Darwin. 



To the great Cuvier a natural system meant an assemblage of groups 

 having a common plan of structure, and he was enraged by Geoffroy 

 St. Hilaire's attempt to put all animals from the bottom to the top in a 

 straight line. A common plan of structure might only mean that 

 idea which best expressed the outcome of a wide study of structure; 

 but to those who tried to peer behind the scenes it meant not seldom 

 to fathom the creation of the world ; and it required no vivid imagina- 

 tion to add that it gives an insight into the plan by which the world 

 was created. 



A historian of the times wrote: 



Yet in fact the assumption of an end or purpose in the structure of organ 

 ized beings appears to be an intellectual habit, which no eflforts can cast off, 

 It has prevailed from the earliest to the latest ages of zoological research 

 appears to be fastened upon us alike by our ignorance and our knowledge . . 

 and the doctrine of unity of plan of all animals, and the other principles asso 

 ciated with this doctrine, so far as they exclude the conviction of an intelligible 

 scheme and a discernible end, in the organization of animals, appear to be 

 utterly erroneous. 



Contrast, in passing, this pious conviction with Geoffro/s modest 

 lines : 



