278 



SCIENTIFIC THOUGHT. 



2. 



"Kvolu- 

 tion." 



exact language. It is only in the second half of the 

 nineteenth century that the many independent lines of 

 reasoning, the fragments of the great doctrine of develop- 

 ment, have been united together, that the search after the 

 principles or laws which govern the restless change has 

 been rewarded by a certain number of definite results, 

 and that what was once vague, fanciful, and legendary 

 has become a leading idea in all the natural sciences. 

 As in other instances which we have had occasion to 

 notice, so also in this case, the appearance of clearer and 

 more definite ideas has been heralded and helped by a 

 novel mode of expression, by a new vocabulary. The 

 word " evolution " has in this country done much to 

 popularise this way of regarding natural objects and 

 events : abroad, the word has not met with the same 

 popular acceptance. It was known there and used in 

 science and literature when it was yet unknown in this 

 country, and has in consequence not been monopolised in 

 the same way as in the English language, to denote the 

 continuous and orderly development of states and forms 

 of existence. 1 Moreover, it has been identified in this 



1 On the older and modern use 

 of the word "evolution" in the 

 English language see Huxley's 

 article in the 9th ed. of the 

 ' Ency. Brit.' It is reprinted in 

 his collected essays with the title 

 "Evolution in Biology." Accord- 

 ing to Huxley, the term "evolu- 

 tion " was introduced in the former 

 half of the eighteenth century in 

 opposition to " epigenesis." The two 

 terms denoted the two theories of 

 the generation of living things, by 

 development of pre-formed germs 

 (pre-formation) or by successive 

 differentiation of a relatively homo- 



geneous rudiment (after -formation). 

 Harvey, the expounder of the latter 

 theory against Malpighi, who em- 

 braced the former, calls the first 

 "metamorphosis." Leibniz, Bon- 

 net, and latterly Haller, were "evolu- 

 tionists" in the older sense of the 

 word ; Harvey, C. F. Wolf, and 

 the modern school of embryologists, 

 with von Baer as its most eminent 

 representative, were adherents of 

 the originally Aristotelian theory 

 of " epigenesis." " Nevertheless," as 

 Huxley says, " though the concep- 

 tions originally denoted by ' evolu- 

 tion ' and ' development ' were 



