PROPERTIES OP THE LEAP OP DION2EA. 
35 
hairs of opposite lobes, and subjected, first on one side and then on the other, in each 
experiment, to two series, each consisting of ten successive excitations. The table 
shows the results. The letter f or m indicates that, in the case to which it relates, 
the fixed or movable electrode was on the excited lobe. In all the experiments the 
excitation was effected by touching a sensitive hair with a camel-hair pencil. The 
hair touched is indicated. After each observation the difference was compensated. 
The mean differences are given in the last column. All of the leaves were tested 
by observing the excitatory effect in each lobe separately when led off as in the 
fundamental experiment. 
No. of 
experiment. 
Which 
lobe 
excited. 
Which hair 
touched. 
Which 
electrode on 
excited 
lobe. 
Character of variation. 
Difference. 
I. 
R. 
Proximal . 
M. 
Monophasic, —>39'1. 
+ 0*011 D. 
L. 
Ditto 
E. 
Diphasic, +11*7, —21*2 , . . 
+ 0*007 D. 
II. 
L, 
Proximal , 
F. 
Monophasic, +6*2. 
-0*01 D. 
R. 
Ditto 
M. 
Diphasic, —2, +25*4 .... 
-0*02 D. 
III. 
R. 
Proximal . 
M. 
Diphasic, — 3*2, +18*8. . . . 
Monophasic, +22*2. 
-0*007 D. 
L. 
Ditto 
F. 
-0*005 D. 
IY. 
L. 
Distal . . 
F. 
Diphasic, +3*4 pause .... 
+ 7*4 (from zero)* . 
+ 0 023 D. 
R. 
Ditto . 
M. 
Diphasic, +9*8, —2*9 .... 
+ 0*023 D. 
In leaves I. and II. the difference between the two lobes was so great that the 
leaves could scarcely be considered normal. In leaf III. the variation was normal on 
both sides, but the first phase was larger on the left than on the right ( — 8‘5, 
on the left, —4'4, +7*8 on the right). In leaf IV. the first phase was nearly equal 
on both sides (—30'0 on the left, —31 *6 on the right), and was followed in both cases 
by a normal after effect. But these facts afford no clue to the understanding of the 
results recorded in the table, excepting in so far as they show that in a well-balanced 
leaf— i.e., one which responds to excitation with some degree of equality—whichever 
lobe was excited directly had the advantage over the other in the compound variation. 
That this was so was confirmed by the observation that in leaf IV. the negative phase 
of the variation, as observed with opposite contacts (the fundamental experiment), was 
much smaller (—18‘4 on the left, — 2S‘6 on the right) when the opposite lobe was 
excited than when a hair adjacent to the leading off electrode was touched. The only 
general conclusion that I venture to draw from the experiments is a negative one, 
namely, first, that the differences which are observed between the excitatory effects 
in the two cases are as little due to mere inequality of response in the two lobes as to 
* To be read thus:—In the first phase, the meniscus moved from zero of the scale to —3*4, in the 
second, after a pause, from 3*4 to 7*4 in the same direction. 
F 2 
