S. SPIEGELMAN AND A. M. CAMPBELL 



of an essential metabolite. He thus forecast his own discovery 

 (51) of the "bactogen" as well as the independent development 

 by Novick and Szilard (57) of what they call the "chemostat." 



It is not surprising that whenever limitations are imposed, 

 whether they be of energy (35), inducer (60), or of a required 

 metabolite, linear rates of enzyme synthesis are observed. One 

 must therefore agree that enzyme synthesis need not be always 

 autocatalytic. However, linear and other (24) deviations from 

 autocatalytic kinetics may signify the presence of restrictions 

 which prevent the exhibition of the exponential kinetics of which 

 the system is capable. In any case, such deviations cannot 

 be accepted as compelling evidence against the existence of 

 exponential rates of enzyme formation. 



The presence of a rising rate of enzyme synthesis means 

 that some self-reinforcing activation of the enzyme-forming 

 system is occurring during the induction. A further analysis of 

 the mechanism and the role of the inducer in it requires the 

 application of other analytical devices. One of these approaches 

 is genetic, and we turn now to the data derived from its use. 



THE INHERITANCE OF ENZYME-FORMING CAPACITY AND 

 ITS SIGNIFICANCE FOR THE ROLE OF THE INDUCER 



Kinetic arguments, no matter how refined, cannot of them- 

 selves be decisive. It was fortunately possible to examine the 

 question of the autocatalytic nature of enzyme formation by 

 completely different means and one which provided a more 

 subtle and surprisingly fruitful method for further probing into 

 the question of inducer function. The potentiality of examining 

 induction by essentially genetic methods was suggested by the 

 discovery of a new and pathological type of induction. Winge 

 and Roberts (102) labeled their new phenotype "long term 

 adapter" because it was much slower in adapting to galactose 

 than the normal type. They further showed that the "slow" 

 character was determined by an allele (g^), which was recessive 

 to the wild type (G). 



Spiegelman, Sussman, and Pinska (89) undertook an an- 



136 



