EVOLUTION AND EPIGENESIS. 215 



and self-division in its primordial units. It teaches us that the 

 germ may stand for two things, which the old philosophy held 

 to be irreconcilable : namely, something already accomplished 

 as well as something yet to be accomplished. 



The " something " with which development begins was sadly 

 underestimated in the old epigenesis, and as sadly overesti- 

 mated in the old evolution. Think of Harvey protesting that 

 it is a mistake to look for any such thing as '' prepared matter^' 

 in the egg (Ex. XLIV), and insisting that even his " antege- 

 nial colliqiiamenUmi " could not preexist, but must come into 

 existence after the egg, as a result of decoctive liquefaction of 

 the albumen (Ex. XVI). And, at the other extreme, see Bon- 

 net and Haller denying generation altogether, claiming that all 

 the essential (organic) parts of the adult organism preexist 

 ready-formed in the germ, and that development means noth- 

 ing but expansion of the organs by the infiltration of matter 

 wholly foreign to them. 



The two views missed the mark by over-shots in contrary 

 directions. The one claimed too much preformation; the other 

 too much post-formation. Both were equally blind to the law 

 of genetic continuity, and so the choice lay between the 

 mechanical difficulties of formation de novo and the bald fatali- 

 ties of emboUement. It was the option of Scylla or Charybdis. 



There is some analogy with our present position, but it must 

 not be mistaken for anything more than a superficial resem- 

 blance. Our present difficulties do not arise in consequence of 

 a return to the old position, but rather as the result of its aban- 

 donment, and a general advance that enables us to approach the 

 problem from a much higher level. Organic development is 

 still an unsolved problem, but it is a problem which rides the 

 crest of one of the most revolutionary waves that has ever 

 deluged human philosophy. We have but too lately experi- 

 enced the shock and heard the reverberations of the tidal 

 advance in every direction, not to realize how profoundly 

 changed is our whole position. What is development 1 is a 

 question as old as human inquiry; but does sameness in the 

 form of the question indicate identity of standpoints .? Embry- 

 ology, histology, cytology, and all the sciences that are now 



