STUDIES ON THE DYNAMICS OF MOEPHOGENESIS 267 



it involves extensive redifferentiation in the isolated part or is 

 chiefly limited to localized outgrowth and differentiation of new 

 tissue, it is development, morphogenesis, just as certainly" as is 

 the formation of an orgaaism from the egg. 



Furthermore, wherever a new whole, a new 'individual' arises 

 in the organic world, there we have before us the problem of 

 heredity. But we must pause here for a moment to consider 

 what we mean by heredity and inheritance. To say that inheri- 

 tance is resemblance between offspring and parent or between 

 related individuals is incorrect, for such resemblance may arise 

 from external conditions acting during development, as well as 

 from something which the reproductive element brought from 

 the past to the beginning of development. To assert that inher- 

 itance is the transmission of characters from parent to off- 

 spring is also unwarranted, since we know nothing of ' characters ' 

 except as thej^ appear in the structure and behavior of the organ- 

 ism during and after ontogeny, and we know but little of trans- 

 mission or its possibilities. 



Godlewski ('09) has recently given the following definition; 

 ''Vererbung ist die Fahigkeit des Organismus den morpholo- 

 gischen Ausgangspunkt seiner Entwicklung aus einem bestimm- 

 ten Teil seines eigenen Korpers auszubilden und vermittelst 

 desselben seine Eigenschaften auf die Nachkommenschaft die 

 sich daraus entwickeln kann, zu iibertragen." This definition 

 does not seem to me to cover the ground exactly or fully; how 

 do we know that the organism differentiates or develops a cer- 

 tain part as the morphological starting point of its development? 

 For it to accomplish this a certain degree of finality would seem 

 to be necessary. And again, we do not know that the organism 

 'transmits' (iibertragt) its characters to anything, indeed there 

 are strong reasons for believing that it does not. 



A definition of heredity which is broad enough to include all 

 kinds of heredity and which does not involve premature and 

 unwarranted conclusions as to the nature of the process of inher- 

 itance, must, it seems to me be somewhat as follow^s: Heredity is 

 the sum total of the inherent capacities or 'potences^ with which a 

 reproductive element of any kind, natural or artificial, sexual or 



