324 Action of the Genetic Material 



constituents to pass the threshold from the previous stable state to the 

 given one. This statement (presented as an alternative for discussion) 

 is a somewhat abstruse formulation of what I called the genically 

 initiated stratification via the conditions of the system. But, Wright 

 continues, though there is, no doubt, considerable truth in this idea, 

 the stability of the changed state is easier to understand if there are 

 self-duplicating materials in the cell which, can be modified chemically 

 and subsequently multiply by duplicating the new chemical constitu- 

 tion. The whole idea thus amounts to controlled mutation of plasma- 

 genes 1 Since the existence of plasmagenes is more than doubtful 

 (according to our previous discussion), not to mention their muta- 

 tions, and since the facts can be completely described in terms of 

 genie actions upon stratifiable substrates, I must repeat that I am not 

 convinced that an interpretation in terms of plasmagenes helps the 

 understanding of genetic determination. Rather, this concept slips in 

 an element of the entelechy type from behind the apparent genetical 

 and biochemical formulation, a thing which Wright certainly does not 

 intend to do. For this reason, other theories involving plasmagenes, 

 which are essentially of the same type as those reported, need not be 

 discussed in detail. Only one more example need be given of what 

 I have just termed the entelechy type of qualities conferred upon the 

 plasmagenes in their interference with genie actions. Spiegelman 

 ( 1948 ) proposed that genie action produces a pool of unspecific pro- 

 tein precursors in the cytoplasm which by action of the plasmagenes 

 are transformed into the specific enzymes. Though this idea was 

 proposed as an explanation of adaptive enzymes, it may also serve as 

 an illustration of our point. 



All in all, "activation of the gene" may still mean either the 

 segregation of the competent substrate with which only the specific 

 genie material can react; or a continuous function of all genie mate- 

 rial on a level which is subthreshold until the proper substratum 

 appears; or the same with a competition for substrate, which is won 

 by the genie material that is somehow specific for the substrate; or an 

 inhibitory action of all substrates, which is locally removed by proc- 

 esses within certain parts of the cytoplasm. All these assumptions are, 

 in the end, the same: a description of the facts of development in 

 terms of genie action and cytoplasmic diversification, whether ex- 

 pressed in general terms or in more specific ones involving unknown 

 molecular configurations. 



Up to this point, our discussion of the so-called gene activation 

 has dealt with features of development as exemplified in Drosophila 



