PROFESSOR VIRCHOW AXD EVOLUTION'. 397 



eorae divorce will be established between the expert and 

 the public, and the slow and natural process of leavening 

 the social lump by discovery and discussion will be dis- 

 placed by something far less safe and salutary. 



The burthen, however, of this celebrated lecture is a 

 warning that a marked distinction ought to be made be- 

 tween that which is experimentally proved, and that 

 which is still in the region of speculation. As to the 

 latter, Virchow by no means imposes silence. He is far 

 too sagacious 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 ought to be warned that the speculative mat- 

 ter is only possible, not actual truth that it belongs 

 to the region of ' belief,' and not to that of demonstra- 

 tion. As long as a problem continues in this specula- 

 tive 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 hy- 

 pothesis as a doctrine: this is inadmissible.' With re- 

 gard to the connection between physical processes and 

 mental phenomena he says: ' I will, indeed, willingly 

 grant that we can find certain gradations, certain defi- 

 nite 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 assert- 

 ing that it will never be possible 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 possible connection as a doctrine 

 of science.' In the next paragraph he reiterates his 

 position with reference to the introduction of such 

 topics into school teaching. ' We must draw/ he says, 



