1901} BRIEFER ARTICLES 425 
| taken from a different bulb under similar conditions. It seems there- 
fore that the results secured are representative and trustworthy. The 
percentages are in all case the proportion of nuclei found dividing. 
Time Normal Yellow Blue Black 
I2 P. M. 18.3 % 13.85% 10.9 % 11.4% 
4 A.M. 14.0 13.6 11.6 12.4 
8 A.M. 143 12.1 10.5 12.7 
I2 A. M. 14.6 13.9 i1.8 12.6 
4 2. M; 13.4 12:5 10.2 14.8 
8 P. M. 13.6 12.1 12.3 
Averages 14.7% 12.6% 11.0% 12.7 % 
In the accompanying figure these same results are represented in 
the form of curves showing the percentage of dividing nuclei under 
each of the four stated conditions of the 
ill wasn’ experiments. 
184-1 ———Yellow It will be seen that in the normal light 
ae the greatest percentage of dividing nuclei was 
ae BS saci found in roots collected at midnight, while in 
let none of the other lights does this same rela- 
ag, tionship hold true. 
196+ —\ 1) ‘In the roots grown 
eae adie 
14% + ER GP 1! in darkness there 
es ad ae el was found the low- 
gee PRE @ Sass SRT, 8 = |] est percentage of di- 
MPS EES "6 Misa viding nuclei,at mid- 
4 a a H night, and the high- 
| 25 pi 6 ee pares a —f] est percentage is 
| al | I at i found at 4:00 P.M. 
|__ PM AM AM AM PM pu Future studies 
must determine if this 
Same relation, as exhibited in the curves shown, exists in cells having 
active chloroplastids during normal photosynthesis. Studies of this 
type are now under way, and further discussion of this subject is 
Teserved until the completion of the investigations mentioned.— 
ARTHUR Carr Lewis, 4 gricultural and Mechanical College, Stillwater, 
Oklahoma. 
