22 DURATION OF THE SEVERAL MITOTIC STAGES 



theory that a confusion actually occurred here. If stages 1 and 2 

 actually respond about the same to heat changes, a clean-cut differen- 

 tiation in classifying them in the early countings and a gradual uncon- 

 scious evolution of conscious criteria in the later thousands, in which 

 stage 2 was crowded in favor of stage 1, would give the phenomena 

 recorded. At no other point in the determinations is there such a diffi- 

 cult distinction to miake, nor is there such another adjacent pair of 

 values that might be accounted for by such an error. However, the 

 much greater duration of stage No. 1 over stage No. 2 precludes the 

 possibiUty of errors in then* distinction, greatly changing the determi- 

 nations for No. 1, the longer one. When we test this possible error 

 by uniting stages 1 and 2 into a single stage, we find the following: 



A A D.atlO°C. = 74.36min.; at 20° C.= 67.49 mm.; at 30° C. = 52.67 

 mm. Qio 10° C. to 20° C.= 1.10; Qio 20° C. to 30° C.= 1.28 



still giving a stage, sluggish hke No. 1, in the 20° to 30° C. temperature- 

 rise response. This indicates strongly that the values calculated for 

 stage 1 are certainly quite correct and those calculated for stage 2 can 

 not be challenged on the grounds of the immediate criticism, and 

 therefore that the striking difference in their calculated temperature 

 reactions is real. 



AVERAGE ABSOLUTE DURATIONS OF THE SEVERAL MITOTIC STAGES. 



PRELIMINARY EXPERIMENTS. 



A further examination of the Stage Index Table (No. 4) of the prelim- 

 inary study reveals no recognizable mitotic wave passing through a suc- 

 cession of mitotic stages and time-intervals. This confirms the evidence 

 of the Method Chart that connecting the high points of the stage index 

 sequence through mitotic stages and time-intervals will not, in the 

 situation-complex existing in the material used, suffice to determine the 

 average absolute durations of the several stages. The procession indi- 

 ces of the preliminary study were worked out in accordance with the 

 principles analyzed in detail in the Method Chart, and the result shows 

 clearly 3 different progressive waves passing, as would be expected, in 

 an orderly manner through successive mitotic stages and time-inter- 

 vals. The calculations from these 3 waves give the average dura- 

 tion of the entire mitotic cycle of these 10 active stages to be 172.2 

 minutes. Dividing this value in proportion to the average relative 

 duration of the several stages, the average absolute duration of the 

 10 successive stages is as follows (in minutes) : 



77.02, 38.19, 16.06, 4.58, 1.32, 1.65, 1.53, 4.83, 6.31, 20.59 



These results are based upon large portions of 3 waves, while those in the 

 Method Chart were based upon only 2 waves. If, as is seen, the average 



