PROPERTIES OF THE LEAF OF HIONiEA. 
37 
The numbers given are the means of two accordant observations at each period, before 
each of which the difference was compensated. 
In a second leaf, led off in precisely the same way, the general character of the 
excitatory effect was observed with the electrometer. The fixed electrode was on the 
left lobe. When that lobe was excited electrically (as in the last experiment) the 
variation was diphasic, the first phase being positive. When the right lobe was 
excited (x on right lobe), the variation was also diphasic, with opposite signs. The 
rheotome gave the following, the closing time being 0*075":— 
x On left lobe. 
x On right lobe. 
P. 
M. 
At 0-10". 
+ 9 
- 7 
At 0-20". 
+ 24 
-18 
At 0-30". 
+ 27 
-20 
At 0'40". 
+ 20 
- 9 
At 0-50”. 
+ 4 
- 4 
The numbers express in each instance the means of two observations, before each 
of which, as usual, the difference was compensated. The resistance exceeded 
160,000 ohms, notwithstanding that the utmost pains were taken in making the 
leading off contacts. 
In a third experiment we had at our disposal a large vigorous leaf. The fixed 
contact was on the right lobe. The leaf was subjected to 48 excitations during a period 
of 70 seconds, to all of which it responded. Its resistance was such that 100 scale 
of the galvanometer corresponded to 0’45 D. The excitations gave with the rheotome 
(the duration of closure of the galvanometric circuit being one-fifth of a second) the 
following results:— 
* On right lobe. 
x On left lobe. 
F. 
M. 
At 0-20". 
+ 28 
-33-5 
At 0-4". 
+ 44 
-24-3 
At 0-6". 
+ 50 
- 3-0 
At 1-0" . 
0 
0 
These observations show, even more strikingly than the previous ones, how com¬ 
pletely Professor Munk is mistaken in his statement that, provided the leading off 
is the same, the seat of excitation is a matter of indifference. They also serve to 
strengthen the conclusion that the intensity of the electrical disturbance is greater in 
