Physiology of Reproduction in Domestic Fowl 345 



as from a critical examination of the earlier literature of the sub- 

 ject the writer has reached the provisional conclusion that the 

 uterus actively shapes the egg by muscular contractions during and 

 preceding the deposition of the shell, and that it is in this v^ay that 

 the finer and individual form characteristics of eggs are deter- 

 mined. Such a viev^ does not deny that the uterus may and does 

 at the same time act as an elastic wi^alled mold. It is hoped that 

 it v^ill be possible later to get more complete direct physiological 

 evidence on this matter than now exists. 



It will of course be recognized that while it is obviously proper 

 to speak of the morphogenetic activity of the oviduct in connection 

 with egg production, the kind of morphogenetic activity here in- 

 volved is different from that usually implied by the use of this term. 

 The form of the egg is not immediately determined by processes 

 of cell division and differentiation. Instead we are dealing with 

 the formed products of a purely physiological, as distinct from 

 developmental, process. Recognizing this fact it is no less impor- 

 tant to investigate cases of such "physiological morphogenesis" 

 (if such an expression is permissible), particularly if, as will be 

 shown in the present paper, it closely parallels or indeed appears 

 to be identical with "developmental morphogenesis" in certain 

 important respects. 



REGULATION IN MORPHOGENESIS 



By the expression "regulation in morphogenesis" is commonly 

 understood the production by an organism of adaptive or normally 

 formed structures or parts under conditions or from beginnings 

 which are in some degree abnormal or unusual. Regulation is a 

 process of adjustment. In the words of Driesch ('01, p. 92): 

 "Regulation ist ein am lebenden Organismus geschehender Vor- 

 gang oder die Aenderung eines solchen Vorgangs, durch welchen 

 oder durch welche eine irgendwie gesetzte Storung seines vorher 

 bestandenen "normalen" Zustandes ganz oder theilweise, direkt 

 oder indirekt, kompensirt und so der "normale" Zustand oder 

 wenigstens eine Annaherung an ihn wieder herbeigefuhrt wird." 



The whole process of normal development of an organism is 



