74 
Blackman and Paine.—Sludies in the 
pulvinus raised just above the liquid where the air was only slightly below 
the temperature of the bath; this, as seen below, caused no contraction of 
the pulvinus. A and A' give the angles which the pulvinus made with the 
petiole before and after raising. 
me in 
’mites. 
Treatment of Pulvinus. 
A. 
A 1 . 
Conductivity 
in Gemhos. 
Pate of 
Exosmosis . 
o 
Leaf cut 
_ 
_ 
_ 
_ 
5 
Experiment started 
125° 
— 
— 
— 
JO 
Raised 
>43° 
1 47° 
56'2 
— 
J 5 
,, and stimulated” 
J 57° 
112 ° 
62*4 
6*2 
20 
» 
I41 ° 0 
141 0 
68-2 
5*8 
25 
153 
153° 
72*6 
4*4 
30 
,, and stimulated 
154 0 
127 ° 
7 6 *3 
3'7 
35 
>> 
151° 
154° 
8o*6 
4 3 
4° 
154° 
L c 4° 
84*1 
3*5 
45 
„ and stimulated 
154° 
118 ° 
86-8 
2*7 
5° 
99 
I45 o 
145° 
9°‘9 
4 1 
55 
r 
149 
149° 
93-3 
2*4 
6o 
,, and stimulated 
I 49° 
114 ° 
95-6 
2-3 
6 5 
9 9 
143° 
14 3° 
98-8 
3 2 
7o 
99 
!43° 
143° 
100*9 
2*1 
75 
,, and stimulated 
14 3° 
110 ° 
102*7 
i*8 
8o 
„ 
136° 
136° 
105*8 
3 1 
85 
n 
136° 
136° 
107*7 
i*9 
00 
., and stimulated 
136° 
109 ° 
109*3 
j*6 
95 
„ 
120° 
122° 
112*4 
31 
100 
f 9 
135° 
135° 
114*0 
i*6 
105 
,, and stimulated 
134° 
106 ° 
115-5 
i*5 
I JO 
117 0 
11 7° 
118*7 
3 2 
115 
>5 
125 0 
125 0 
I 20*0 
i-3 
120 
,, and stimulated 
9 9 
12 5 0 
95 ° 
121*0 
1 *o 
125 
uo° 
I IO° 
123*6 
2 6 
130 
yy 
119 0 
119 0 
124*9 
1 *3 
135 
Experiment ended 
J1 9° 
125*7 
o*8 
The result shown in Table I is typical of many. It shows that the cut 
pulvinus kept immersed in warm water will exhibit a large number of 
contractions when suitably stimulated. The mere fact that the pulvinus 
will continue to respond to stimulation under these conditions is sufficient in 
itself to negative the hypothesis that the loss of turgor on contraction is 
dependent on an escape of osmotic substances from the tissues. For, with 
the internal tissues of the pulvinus freely exposed to warm water not only 
at the base but at the sides, such substances, if they left the cell, would pass 
rapidly into the surrounding fluid. There these substances would be lost to 
the tissues; for it is hardly conceivable that they could be reabsorbed, at 
least within any short period. Again, it is hardly possible that, if at each 
contraction there is a loss of osmotic substances sufficient to markedly 
reduce the turgor of the cells, such substances could be produced again at 
such a rate as to allow the pulvinus to continue to contract every fifteen 
minutes during two hours. 
In nearly all the experiments a slow exosmosis of electrolytes from the 
cut surfaces of the pulvinus is to be observed. The rate of this exosmosis, 
apart from contractions of the pulvinus, falls off steadily for a long period. 
