PROFESSOR V1RCHOW AND EVOLUTION 417 



forcing it upon the public at large. His "we," I submit, 

 needs definition. If he means that the theory of evolu- 

 tion ought to be introduced into our schools, not when 

 experts are agreed as to its truth, but when the commu- 

 nity is prepared for its introduction, then, I think, he is 

 right, and that, as a matter of social policy, Dr. Haeckel 

 would be wrong in seeking to antedate the period of its in- 

 troduction. In dealing with the community great changes 

 must have timeliness as well as truth upon their side. But 

 if the mouths of thinkers be stopped, the necessary social 

 preparation will be impossible; an unwholesome 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 displaced by some- 

 thing far less safe and salutary. 



The burden, 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 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. 

 44 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 matter is only possible, not 

 actual truth that it belongs to the region of "belief," and 

 not to that of demonstration. As long as a problem con- 

 tinues 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 



