Genie Control of Development 421 



orderly series of determinative steps by which increasingly smaller 

 embryonic areas are narrowed down to single developmental poten- 

 cies. As we have seen, the facts require a genie action which produces 

 some substance with a definite velocity, thus emphasizing the role of 

 the kinetics of genie action. Furthermore, threshold conditions are 

 involved which must also be genically controlled, and which control 

 the amount of the determining material needed for irreversible action. 

 These basic gene-controlled processes are found to interact with simul- 

 taneous and independently controlled gradients of production or of 

 flow of the determining stuffs, and this again is interlocked with growth 

 processes, again independently determined. 



The last basic feature is the so-called "activation of the genes," 

 meaning that such parts of the always present total genie material 

 become active, produce or make reactive its special products, for 

 which the specific, competent substrate has been made available by 

 one or the other processes of cytoplasmic diversification (stratifica- 

 tion). 



In the development of tertiary (etc.) patterns, repetitions of the 

 primary and secondary types of basic genie action may come into 

 play, as well as the other types of genie action I have mentioned. 

 Here the simple biochemical actions of the one gene — one synthetic 

 step type come into play in the control of specific products like pig- 

 ments or metabolites, actions which are intracellular but allow a 

 chance of diffusibility or migration of their products. Another such 

 tertiary action would be the initiation of polyploidy and its conse- 

 quence, stoppage of genie actions except definite types of syntheses, 

 probably by a specific cytoplasmic segregant. Here belong also the 

 specific genie actions on growth, initiation or stoppage of cell division, 

 allometric growth by directly affecting the partial growth processes, 

 which are expressed in the constants of the allometric growth formula. 

 Gradients of growth hormones produced under genie control are a 

 part of the picture, and so, also, are the known genically controlled 

 effects upon the place and direction of cell division, cell elongations, 

 and degenerations. 



It seems to be impossible to construct a model that would permit 

 us to visualize the entirety of these interplaying processes at once. 

 Such a model would have to contain the features of the Chinese carv- 

 ings of a set of ivory spheres, one inside the other; each sphere, down 

 to the smallest, would have to contain a set of next grade spheres; 

 and all these, again such sets. Further, each sphere and subsphere 

 would have to contain a tridimensional set of coordinates on which the 



