13S 
Sydney 11. Vines. 
If this lable be trealeil in llie same way as the fonner onc, the effect 
of exposure to light is brought out more markedly. Here the average is 
0 . 13 nearly, the maximum is reached al 3 p. m. and the descent be- 
gins at 3 p. m. 
2.70 
2.70 .. . 
. 2.70 — 2.70 — 0.13 
_ 
0.13 — 
2.30 . . . 
. 2.30 — 2.70 — 0.13 
= 
0.33 — (light) 
2.90 ... 
. 2.90 — 2.30 — 0.13 
= 
0.47 + 
2.70 ... 
. 2.70 — 2.90 — 0.13 
= 
0.33 — (light) 
3.20 ... 
. 3.20 — 2.70 — 0.13 
= 
0.37 + 
maximum 
3.50 . . . 
. 3.50 — 3.20 — 0.13 
= 
0.17 + 
2.90 
. 2.90 — 3.30 
= 
0.60 — (light) 
3.20 ... 
. 3.20 — 3.50 
= 
3.30 — 
d e s c e n t 
2.80 ... 
. 3.50 — 2.80 
= 
0.37 +. 
Front these observations il appears that light exerts considerable in- 
üuence the diminishing the acceieration of growth. lt is noticeable that, 
as a rule, the acceieration falls below the average only during the hour 
of exposure to light, and that it rises in the subsequent hour above the 
average, but the acceieration in Ihe hour afler exposure to light is not 
so great as it was in the hour before exposure. This is an indication 
that the effect of the action of light persists for a time after the actual 
exposure has cessed. This persistent effect (Nachwirkung) was noticed 
by Sachs and Piuntl to occur in the case of internodes and leaves. ln 
consequence of the very simple strueture of the hypliae the elfects pro- 
duced by the action of light are rapidly manifesled, but the persistence 
of the action is not great. 
II the measurements be made al shorter intervals, the persistent effects 
become more evident. The following lable and curve consist of half- 
hourly measurements. 
Half-hourly 
growth. 
TetOperu- 
ture. 
7'/ä—8 a. m. 
0.30 
24.8« C. 
8 V* « 
0.30 
25.0 
9 , 
0.30 
23.3 
»Vs . 
0.90 
23.6 
10 , 
1.10 
25.8 
*0‘/s » 
1.00 
25.7 * 
1.10 
25.9 
n'/ 3 ., 
1.40 
26.3 
12 — 
1.20 
26.7 * 
I 2 V 2 P- nl 
1.40 
26.4 
1 „ 
1.50 
26.1 
* light. 
The average in this case is 0.12 per 
half hour. 
