Snap. XIII. TRANSMISSION OF MOTOR IMPULS#. 315 
touched towards the midrib and opposite lobe, or 
towards the outer parts of the same lobe. 
Two slits near each other, both parallel to the mid- 
rib, were next made in the same manner as before, one 
on each side of the base of a filament, on five distinct 
leaves, so that a little slip bearing a filament was con- 
nected with the rest of the leaf only at its two ends. 
These slips were nearly of the same size; one was care- 
fully measured ; it was ‘12 of an inch (3:048 mm.) in 
length, and ‘08 of an inch (2:032 mm.) in breadth; 
and in the middle stood the filament. Only one of 
these slips withered and perished. After the leaf had 
recovered from the operation, though the slits were 
still open, the filaments thus circumstanced were 
roughly touched, and both lobes, or one alone, slowly 
closed. In two instances touching the filament pro- 
‘duced no effect; but when the point of a needle was 
driven into the slip at the base of the filament, the 
lobes slowly closed. Now in these cases the impulse 
must have proceeded along the slip in a line parallel 
to thé midrib, and then have radiated forth, either 
from both ends or from one end alone of the slip, over 
‘the whole surface of the two lobes. 
Again, two parallel slits, like the former ones, were 
made, one on each side of the base of a filament, at 
right angles to the midrib. After the leaves (two in 
number) had recovered, the filaments were roughly 
touched, and the lobes slowly closed; and here the 
impulse must have travelled for a short distance in a 
line at right angles to the midrib, and then have 
radiated forth on all sides over both lobes. These 
several cases prove that the motor impulse travels in 
all directions through the cellular tissue, independently 
of the course of the vessels. 
With Drosera we have seen that the motor impulse 
