PROFESSOR VIRCHOW AND EVOLUTION. 401 



act, they prolong the method of nature from the pre- 

 sent into the past. Here the observed uniformity of 

 nature is their only guide. Having determined the 

 elements of their curve in a world of observation and 

 experiment, they prolong that curve into an antecedent 

 world, and accept as probable the unbroken sequence of 

 development from the nebula to the present time.' 

 Thus it appears that, long antecedent to the publication 

 of his advice, I did exactly what Professor Virchow 

 recommends, showing myself as careful as he could be 

 not to claim for a scientific doctrine a certainty which 

 did not belong to it. 



I uow pass on to the Belfast Address, and will cite 

 at once from it the passage which has given rise to the 

 most violent animadversion. ' Believing as I do in the 

 continuity of nature, I cannot stop abruptly where our 

 microscopes cease to be of use. At this point the vision 

 of the mind authoritatively supplements that of the 

 eye. By an intellectual necessity I cross the boundary 

 of the experimental evidence, and discern in that 

 "matter" which we, in our ignorance of its latent 

 powers, and notwithstanding our professed reverence 

 for its Creator, have hitherto covered with opprobrium, 

 the promise and potency of all terrestrial life.' With- 

 out halting for a moment I go on to do the precise 

 thing which Professor Virchow declares to be necessary. 

 ' If you ask me,' I say, * whether there exists the least 

 evidence to prove that any form of life can be developed 

 out of matter independently of antecedent life, my 

 reply is that evidence considered perfectly conclusive 

 by many has been adduced, and that were we to follow 

 a common example, and accept testimony because it 

 falls in with our belief, we should eagerly close with 

 the evidence referred to. But there is in the true man 

 of science a desire stronger than the wish to have his 



