PROFESSOR VIRCHOW AND EVOLUTION 421 



know something of our remotest ancestry. On its first 

 detachment from the sun, life, as we understand it, could 

 not have been present on the earth. How, then, did it 

 come there ? The thing to be encouraged here is a rever- 

 ent freedom a freedom preceded by the hard discipline 

 which checks licentiousness in speculation while the 

 thing to be repressed, both in science and out of it, is 

 dogmatism. And here I am in the hands of the meet- 

 ing, willing to end, but ready to go on. / have no right 

 to intrude upon you unasked the unformed notions which are 

 floating like clouds, or gathering to more solid consistency in 

 the modern speculative mind." 



I then notice more especially the basis of the theory. 

 414 Those who hold the doctrine of evolution are by no 

 means ignorant of the uncertainty of their data^ and they 

 only yield to it a provisional assent. They regard the neb- 

 ular hypothesis as probable; and, in the utter absence of 

 any proof of the illegality of the act, they prolong the 

 method of nature from the present 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 un- 

 broken 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 now 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 conti- 



