THE PROBLEM OF ORGANIC DEVELOPMENT. 179 



of development, which leaves heredity to recapitulate in the absence of the original 

 causes. 



When we put upon heredity the task of recapitulating, in the sense of echo-like 

 reverberations of ancestral experiences, or by the aid of an omnipotent entelechy, 

 or through swarming pangen-deities, the door of mystification is wide opened. The 

 unity of ontogeny and phylogeny is lost sight of, and recapitulation looks like a 

 stupendous myth invented in order to bring together two independent miracles. 



On the other hand, when we recall that ontogeny, or development, circumscribes 

 the whole field, that recapitulation is the law throughout this field — a law referable 

 everywhere and always to primordial processes physico-chemically determined, such 

 as assimilation, growth, and self-division — then it becomes a most impressive fact, 

 with no shadow of myth about it. 



When the crystal recapitulates the form and symmetry of other crystals formed 

 of the same material under like conditions, we are content to view the matter from 

 a physical standpoint, and we postulate no ancestral echoes, no entelechies, no 

 mysteriously circulating pangens. Recapitulation in the organic world is in prin- 

 ciple the same. It calls for no architect, no agencies of any description except the 

 physico-chemical elements combined in a system of metabolic relations, to which 

 we give the name germ-cell. This germ-cell develops true to its species and type; 

 another germ-cell from the same parents does the same; hundreds and thousands 

 of these cells repeat the same steps, at the same times or at different times. They 

 do not imitate, they do not catch the art from one another; they do precisely what 

 they are physically bound to do, each for itself, and each the same just because each 

 is the unit-system of energies. All reproduction is recapitulation in the same sense. 

 Recapitulations are alike because the germ-cells in which they occur are alike, and 

 germ-cells are alike because they arise by equal self-division of mother cells. Like- 

 ness is not an infection; it is not transmission at all; it is wholly and only original 

 wherever it appears in development. 



But if this be true, what becomes of transmission, pangen theories, and circu- 

 lating unit-characters? We have long been taught that heredity means transmis- 

 sion, and upon this idea theories have been built. 



Every theory founded on the postulate of unit-characters or specific determi- 

 nants stored in the nucleus is necessarily committed to some form of centrifugal 

 distribution during the course of development. Herein every such theory breaks 

 down, for it is utterly inconceivable that preformed specific elements could ever be 

 transported each in its time to a particular point in such a complex mosaic field as 

 the organism represents. It is, I believe, a waste of time to try to conceive develop- 

 ment as thus prepunctuated in all its space and time relations. It is to indulge in 

 ultra-scientific teleology. 



When we take from these pangen deities all that speculation has injected into 

 them or wrapped around them, nothing remains but physical elements in self- 

 sustaining organic relations. In brief, we have a primordial germ-cell of the same 

 specific constitution as the mother-cell that preceded it. The mother-cell transmits 

 nothing. When it divides into two daughter-cells it merely divides itself, and each 

 moiety has the constitution it had before division. If, then, the daughter-cell is 

 an exact copy of the mother-cell, there is no wonder, since it really is the mother- 

 cell in substance, constitution, behavior, and potentialities. It is all this, and yet 



