WILLIAM R. AMBERSON 



543 



perature, and I have used this characteristic to prepare luciferin 

 solutions of different concentrations, as will shortly be described. 



2. Experimental Errors. 



In quantitative work with unstable organic substances, errors are 

 certain to appear, no matter how carefully the manipulation may be 



o 



40 



80 



Time 



120 



160 



Fig. 2. Identical solutions. The values check within the photographic error. 

 Abscissae represent time in mm. along the film; ordinates, logarithm of intensity. 



controlled. I have made every effort to hold all factors constant, 

 except the one under investigation, but small and uncontrollable 

 variations undoubtedly have been present. It is impossible, for 

 instance to throw all of the enzyme solutions from their containing 

 pipettes. A small amount remains upon the walls. This amount is 



