THE BELFAST ADDRESS 183 



ieiglits a dozen species of Ammonite, none of wiiicli 

 passes beyond the particular zone of limestone, or clay, 

 into tlie zone below it, or into tliat above it.*' In tbe 

 presence of such facts it was not possible to avoid the 

 question: Have these forms, showing, though in broken 

 stages, and with many irregularities, this unmistakable 

 general advance, been subjected to no continuous law of 

 growth or variation? Had our education' been purely 

 scientific, or had it been sufficiently detached from influ- 

 ences which, however ennobling in another domain, have 

 always proved hinderances and delusions when introduced 

 as factors into the domain of physics, the scientific mind 

 never could have swerved from the search for a law of 

 growth, or allowed itself to accept the anthropomorphism 

 which regarded each successive stratum as a kind of me- 

 chanic's bench for the manufacture of new species out of 

 all relation to the old. 



Biased, however, by their previous education, the great 

 majority of naturalists invoked a special creative act to ac- 

 count for the appearance of each new group of organisms. 

 Doubtless numbers of them were clear-headed enough to 

 see that this was no explanation at all — that, in point of 

 fact, it was an attempt, by the introduction of a greater 

 difficulty, to account for a less. But, having nothing to 

 offer in the way of explanation, they for the most part 

 held their peace. Still the thoughts of reflecting men nat- 

 urally and necessarily simmered round the question. De 

 Maillet, a contemporary of Newton, has been brought into 

 notice by Professor Huxley as one who **had a notion of 

 the modifiability of living forms.'* The late Sir Benjamin 

 Brodie, a man of highly philosophic mind, often drew my 

 attention to the fact that, as early as 1794, Charles Dar- 



