Genie Control of Development 333 



advances. This loss was the inevitable logical consequence of the 

 analytical methods employed. 



"The present knowledge of the biochemical constitution of the cell 

 was achieved largely by the use of destructive methods. Trained in 

 the tradition of the theory of solutions, many a biochemist tends, even 

 today, to regard the cell as a 'bag of enzymes.' However, everyone 

 realizes now that the biochemical processes studied in vitro may 

 have only a remote resemblance to the events actually occurring in the 

 living cell. 



"It is less obvious that the method of genetics, although it in- 

 volves no 'bloodshed,' is as analytical in its essence. Indeed the 

 'resolving power' of this method is amazing. It provides us with a 

 picture of the cell's nuclear constitution with unequaled 'definition.' 

 But, so long as the basis of genetics is the study of differences, it can- 

 not be expected to give us an undistorted picture of the cell as a 

 whole. The integrated character of the cell, which is its fundamental 

 property, is bound to escape our notice most of the time. 



"These statements are not intended to imply that the current 

 analytical trends and methods are bound to be fruitless. All I want to 

 convey to you is that equal emphasis should be placed on the study 

 of the processes of cell integration. 



"Neither should my opinions be taken as a sign of defeatism, for 

 they are based on the belief that ultimately cell integration will find 

 its explanation in terms of knowable, if not known, molecular struc- 

 tures and forces . . ." 



C. KINETICS OF GENIC ACTION 



The term "kinetics" seems somewhat grandiloquent, if we think 

 of the exactness of chemical kinetics, though there have been numer- 

 ous attempts to prove that genie action is of the type of a monomolec- 

 ular reaction. What we mean here is that genie action involves a 

 succession of exactly timed events which implies that rates, velocities, 

 and thresholds enter the picture, whatever the qualitative nature of 

 the reactions and their final products. If we are dealing with the 

 genetic control of development, we can think only very rarely of 

 specific reactions, since we are dealing with the over-all effects of many 

 interdependent reaction chains which are individually not analyzable. 

 Physiological genetics, which attacks the problem of genie control of 

 development, deals mainly with quantitative processes and their over- 

 all effect in time and space. It tries to find the rules of genie action by 



