2i6 THEORETICAL BIOLOGY 



Only as inference from their effects can we say that 

 impulses producing order in space as well as in time invade 

 the protoplasm conformably with plan by operating at one 

 precise spot in the nucleus of the cell on that particular sub- 

 stance which alone is capable of reacting to them. We 

 may say that the genes are " impulsive," but by that term 

 we must not presume a physical energy, following the rule of 

 causality ; rather, we must understand the power to convert 

 an extra-spatial and extra-temporal plan into a physical 

 phenomenon. 



This enables us to understand the point of view of Bunge, 

 who first made the statement that " in activity lies the riddle 

 of life." 



On the other hand, Baer's theory, which compares to a 

 melody the laws regulating the genesis of an organism, assists 

 us greatly in our attempt to understand things. In place of 

 melody, we may also speak of rhythm or of symphony, 

 according to whether we have in mind the rules of the impulses 

 in their simultaneity or in their sequence. 



I must refer once more to the rough comparison I 

 attempted to make when speaking of the way in which a 

 subject clothes itself with properties. With regard to its 

 functions, the subject in the germ-cell is still very simple. 

 But in the genes it possesses a very large number of un- 

 exploited possibilities which will enable it to expand in every 

 direction. As the possibilities are made use of, their number 

 becomes more and more restricted. What the subject gains 

 in shape it loses in fresh life-possibilities. Thus the frame- 

 work slowly increases in complexity and solidity but it be- 

 comes more and more like a machine, and loses one super- 

 mechanical power after the other, until finally there is left 

 in each cell only a remnant of the protoplasm containing the 

 genes that serve for the necessary repairs. The framework 

 \ restricts framework-formation. 



