VIE CHOW AND EVOLUTION. 279 



scientific thought," but of " common modesty " and " common sense." 

 And, though I am indebted to Prof. Clifford for recalling in the Nine- 

 teenth Century for April the public mind in this connection from heated 

 fancy to sober fact, I do not think a brief additional examination of 

 Virchow's views, and of my relation to them, will be out of place here. 

 The key-note of his position is struck in the preface to the excellent 

 English translation of his lecture — a preface written expressly by him- 

 self. Nothing, he says, was further from his intention than any wish 

 to disparage the great services rendered by Mr. Darwin to the advance- 

 ment of biological science, of which no one has expressed more admira- 

 tion than himself. On the other hand, it seemed high time to him to 

 enter an energetic protest against the attempts that are made to pro- 

 claim the problems of research as actual facts, and the opinions of scien- 

 tists as established science. On the ground, among others, that it pro- 

 motes the pernicious delusions of the socialists, Virchow considers the 

 theory of evolution dangerous ; but his fidelity to truth is so great that 

 he would brave the danger and teach the theory, if it were only proved. 

 The burden indeed of this celebrated lecture is a warning that a marked 

 distinction ought to be made between that which is experimentally 

 established, and that which is still in the region of speculation. As to 

 the latter, Virchow by no means imposes silence. He is far too sa- 

 gacious a man to commit himself, at the present time of day, to any 

 such absurdity. But he insists that it ought not to be put on the same 

 evidential level as the former. " It ought," as he poetically expresses 

 it "to be written in small letters under the text." The audience 

 ouo-ht to be warned that the speculative matter is only ^906!S?We, not 

 actual truth — that it belongs to the region of " belief," and not to that 

 of demonstration. As long as a problem continues in this speculative 

 stage it would be mischievous, he considers, to teach it in our schools. 

 " We ought not," he urges, " to represent our conjecture as a certainty, 

 nor our hypothesis as a doctrine : this is inadmissible." With regard 

 to the connection between physical processes and mental phenomena he 

 says : " I will, indeed, willingly grant that we can find certain grada- 

 tions, certain definite points at which we trace a passage from mental 

 processes to processes purely physical, or of a physical character. 

 Throughout this discourse I am not asserting that it will never be pos- 

 sible to bring psychical processes into an immediate connection with 

 those that are physical. All I say is, that we have at present no right 

 to set up this 2^ossible connection as a doctrine of science." In the 

 next paragraph he reiterates his position with reference to the intro- 

 duction of such topics into school-teaching. "We must draw," he 

 says, " a strict distinction between what we wish to teach and what we 

 wish to search for. The objects of our research are expressed as prob- 

 lems (or hypotheses). We need not keep them to ourselves ; tee are 

 ready to communicate them to all the W07'ld, and say, ' There is the prob- 

 lem ; that is what we strive for.' . . . Tlie investigation of such problems, 



