82 Blackman and Paine.—Studies in the 
This last phenomenon is well seen in the ‘ humps ’ in the curve after 
the withdrawal of light. This ‘ after-effect ’ of light was shown in a number 
of cases. 
These results fully confirm the main result obtained by Lepeschkin and 
Trondle, that light increases the permeability of the protoplasm for salts. 
The results show also that the method here used, besides being direct, is 
much superior to that employed by those workers, in that it is far more 
delicate and is also capable of giving practically continuous records. An 
exhaustive study by this method of changes of permeability due to light, 
changes which are probably photochemical in origin, would be of great 
value. 
Effect of Temperature on Rate of Exosmosis. 
A few experiments were carried out by the conductivity method to 
investigate the effect on permeability of slow rise of temperature. 
All the experiments showed that with a rise at the rate of about 5° C. 
in 20 min. the effect of rise of temperature on the rate of exosmosis of 
electrolytes was very slight up to 52 0 . Only when the temperature was 
likely to produce quickly a harmful, and -no doubt irreversible, effect was 
there a marked increase of permeability. 
Table V. 
Effect of Temperahire on the Permeability of the Pulvinus of Mimosa. 
December 17, 1913. Pulvinus with sides sliced, washed in cold water 
for one hour and a quarter. Illuminated by daylight only. Temperature 
raised gradually from 39 0 C. to 64° C. 
Time in 
Temperature . 
Conductivity . 
Rate of In ¬ 
crease of 
Minutes . 
Degrees C . 
Gemhos . 
Coitductivity . 
0 
38-0 
26*8 
_ 
6 
39* I 5 
30-1 
3*3 
12 
4 1 * 1 5 
33 *i 
3 *o 
18 
43-o 
36-0 
2*9 
24 
44 * 55 . 
39-2 
3*2 
30 
46-25 
4 r *9 
2-7 
36 
48-05 
44*8 
2-9 
42 
49*5 
48-0 
3*2 
48 
50-9 
51-6 
3*6 
54 
5 2 *3 
55*4 
3-8 
60 
53-65 
61.1 
5-7 
66 
54-95 
69 *6- 
8*5 
72 
56-15 
81 • 2 
11-6 
58 
84 
57*3 
no-6 
29-4 
58 25 
188-2 
77-6 
90 
59*45 
279.1 
90-9 
96 
60.35 
345*4 
66-3 
102 
61-25 
378*4 
23-0 
108 
62-1 
394 *° 
15 *6 
JI 4 
62-9 
401-2 
7-2 
120 
63*5 
404-0 
2-8 
