178 INHERITA^X•E, FERTILITY, AND SEX IN PIGEONS. 



hosts of atoms migrating from all parts of the body and assembling in germ-cells. 

 This miraculous migration is then followed in the developing germ by an equally 

 marvelous "distribution" of these atoms to their appointed places. Here trans- 

 mission includes two distinct steps — a "centripetal migration" and then a "cen- 

 trifugal redistribution" to points corresponding to the points of departure. 



De Vries abbreviates this hj'pothesis of transmission by cutting out the first 

 step completelj^, for he imagines that his hosts of unit-characters are located in the 

 nucleus from the first, and hence that they require no transportation from the soma. 

 The myth of centripetal migration is dismissed, but that of centrifugal distribution 

 is retained. The abbreviation, then, although in the right direction, amounts to 

 nothing as a simplification, for miracles are not made more comprehensible by 

 reduction in number. 



We have to discard the idea of transmission in toto, not only the centripetal 

 migration conceived by Darwin, but also the centrifugal emigration or distribution 

 from the germ-nucleus to the soma. 



Every theory founded upon the postulate of unit-characters, or specific deter- 

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

 distribution during the course of development; and for each element to be dis- 

 tributed it is necessary to assume either that it is passively transported to its 

 destination or that it finds its own way automatically. In either case it would be 

 nothing less than a miracle for a specific pangen to reach a prescribed point in such 

 a complex mosaic field as the organism represents; and, for this to be fulfilled, not 

 only at the predetermined point, but also at' just the moment for harmonious devel- 

 opment with its immediate neighbors, with symmetrical and correlated groups, 

 with inter- and intra-locking systems, constituting a microcosmic whole, incompara- 

 bly more difficult to grasp than the stellar universe — for all this to be fulfilled is 

 utterly beyond the bounds of scientific credibihty. To try to conceive of normal 

 development as thus prepunctuated in all its space and time relations — as proceeding 

 from ready-made elemental characters, automatically distributing themselves or 

 guided by entelechies — is to indulge in ultra-scientific teleology. 



When we take from these pangen deities all that speculation has fictitiously 

 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 jjotentialities. It is all this, 

 and yet no transfer of qualities has taken place, and it is plain that transference or 

 transmission is absolutely impossible, in the nature of the case. 



Our germ-cell, which inherits nothing — unless, under the spell of usage, we 

 must still continue to say that a cell inherits itself — our germ-cell is from the first a 

 living organism, for it has all the fundamental functions of living organisms, such 

 as assimilation, growth, reproduction, etc. It is in the exercise of these func- 

 tions that development becomes a progressive elaboration, with a physical con- 

 tinuity that admits of periods of comparative rest, but not of breaks in causal 

 sequence. 



