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RAY C. FRIESNER 
initiated it proceeds in a rhythmic fashion; (2) in general, three waves are 
shown in the 24-hour period; (3) the exact time of appearance of maxima 
and minima is dependent upon the time of initiation of activity and shows 
no relation to time of day. 
Lupinus albus. Curves i and 13 show the results of a study of cell 
division in this species. These curves, again, show three waves. Curve i 
shows the first maximum and minimum coming about four hours earlier 
than the corresponding wave in curve 13, though the general character of 
the two curves is strikingly similar and their rhythmic nature is well demon- 
strated. It should be mentioned that the two curves were obtained from 
seeds of different lots. The seeds in both cases began germination at 9 A.M. 
Allium Cepa, Roots from Bulbs. Curve 10 shows three waves of cell 
division with maxima coming at i P.M., 9 P.M., and 5 A.M. ; and the minima 
at 3 P.M., I A.M., and 7 A.M. In comparing this curve with those given 
by Kellicott (14) it is found that the i P.M. maximum and the 3 P.M. 
and 7 A.M. minima correspond to maximum and minima at similar times 
in his curves; while the 9 P.M. maximum of curve 10 comes just two hours 
earlier than the 11 P.M. maximum of his curve I, and one hour later than 
the 8 P.M. maximum of his curve II (page 563 of his paper). The i A.M. 
minimum and 5 A.M. maximum of curve 10 find no equivalents in his 
curve I. In his curve III, however, a third maximum occurs at 5 A.M. 
It should be noted that no figures are given for 5 A.M. in his curve I, and 
hence it is possible that a third maximum may have been missed at this 
hour. Curve 24 is drawn from data obtained a year after that of curve 10, 
and from a different lot of bulbs. Other conditions were the same in both. 
In comparison it is seen that the noon maximum of curve 24 comes at 11 
A.M. instead of i P.M.; the afternoon minimum comes at the same time 
as in curve 10; while an additional low-crested wave, with maximum at 
5 P.M. and minimum at 7 P.M., appears between the times of the first and 
second waves of curve 10. The remaining waves are the same in both. 
Curve 24 thus shows four waves instead of the usual three. In comparing 
these curves with those of Kellicott's on Allium we note that the main 
difference is the larger number of waves here shown. Kellicott used much 
lower temperatures than those used in the present work, and it is possible 
that this may account for the smaller number of waves found in his curves. 
Roots from Seeds. Curve 12 shows results from a study of roots from 
seeds of the Yellow Globe variety. It will be seen that there is little 
difference between this and curve 10 (from bulbs), three waves being found 
in each case. The essential difference is found in the fact that the curve 
does not drop so suddenly to a minimum after both the i P.M. and the 9 
P.M. maxima, in curve 12, as does curve 10. 
Zea everta. Curve 7 shows results obtained from a study of roots from 
seedlings of the White Rice variety. Germination began at 9 A.M. It 
will be seen that the curve is much more oscillatory in character. Karsten 
