PREFA TOR Y NO TE. 



I should be profoundly astonished if they were. What, 

 then, is all the coil about, if we leave aside various 

 irritating sarcasms, which need not concern peaceable 

 Englishmen? Certainly about nothing that touches 

 the present main issues of scientific thought. The 

 " plastidule-soul " and the potentialities of carbon may 

 be sound scientific conceptions, or they may be the 

 reverse, but they are no necessary part of the doctrine 

 of evolution, and I leave their defence to Professor 

 Haeckel. 



On the question of equivocal generation, I have 

 been compelled, more conspicuously and frequently 

 than I could wish, during the last ten years, to 

 enunciate exactly the same views as those put forward 

 by Professor Virchow ; so that, to my mind, at any rate, 

 the denial that any such process has as yet been 

 proved to take place in the existing state of nature, 

 as little affects the general doctrine. 1 



With respect to another side issue, raised by Pro- 

 fessor Virchow, he appears to me to be entirely in 

 the wrong. He is careful to say that he has no 



1 I may remark parenthetically that Professor Virchow's statement 

 of the attitude of Harvey towards equivocal generation is strangely 

 misleading. For Harvey, as every student of his works knows, be- 

 lieved in equivocal generation ; and, in the sense in which he uses the 

 word ovum, "nempe substantiam quandam corpoream vitam haben- 

 tem potentia," the truth of the axiom " omne vivuin ex ovo," popularly 

 ascribed to him, has in no wise been affected by the discoveries of later 

 days in the manner asserted by Professor Virchow. 



