522 KINETICS OF BIOLUMINESCENT REACTION. I 



as it revolves, these bands being separated by a narrower strip some 

 4 mm. wide. An inspection of Plate 1 will make clear the nature of 

 the records resulting from these arrangements. 



Records are taken in a dark room. A length of film is wound 

 tightly about the drum, firmly fastened, and then revolved past the 

 slit windows, where it is affected by light issuing from the reacting 

 solutions placed within the two containers. Records are thus taken 

 simultaneously. The Zimmermann kymograph, whose motion is 

 controlled by a governor, gives quite accurate and constant rotation 

 until the spring has nearly unwound. All records have been made 

 with the spring fully wound up at the beginning of the experiment. 

 No attempt has been made to impress any sort of time record upon 

 the film, in view of the high degree of constancy in the speed of rota- 

 tion. Since absolute measurements of time are of no importance, 

 I have made it a practice to read time in millimeters along the film, 

 and all records presented in this paper are graphed with such values 

 as abscissae. The actual time of rotation of the drum has been 2 

 minutes, and the actual speed of the film 4.123 mm. per second. 



The containers are brought to a standard distance of 1 mm. from 

 the surface of the drum. This leaves a narrow space through which, 

 in darkness, the film strip can be wound into position about the drum. 

 Under these circumstances there is little diffusion to the sides from 

 the slit windows, but a narrow region to right and left is affected by 

 such diffuse light, and this is undoubtedly a factor affecting the 

 records. Because of it, and of the slit width itself, the effect of the 

 light upon any particular halide grain in the revolving film is not 

 instantaneous. Allowing for such dift'usion the exposure time for 

 any particular grain is about half a second. No attempt was made 

 to correct mathematically for these factors of slit width and diffusion, 

 since their effect upon the shape of the curve is slight in any case, 

 and indeed tends to smooth the curve rather than to distort it. 



With the containers correctly adjusted, and the film applied to 

 the drum, aqueous luciferin solutions are added to both vessels. I 

 have made it a uniform practice to use 20 cc. of luciferin solution in 

 each container, measured out with a pipette. To each solution, at 

 the proper instant, while the drum is in rotation, there is added 1 

 cc. of luciferase. The two enzyme solutions have previously been 



