222 DROSERA ROTUNDIFOLIA. [Cuap. XI. 
from the glands of the extreme marginal tentacles does not 
seem to have force enough to affect the adjoining tentacles ; 
and this may be in part due to their length. The impulse 
from the glands of the next few inner rows spreads chiefly 
to the tentacles on each side and towards the centre of the 
leaf; but that proceeding from the glands of the shorter 
tentacles on the disc radiates almost equally on all sides. 
When a gland is strongly excited by the quantity or 
quality of the substance placed on it, the motor impulse 
travels farther than from one slightly excited; and if 
several glands are simultaneously excited, the impulses from 
all unite and spread still farther. As soon as a gland is 
excited, it discharges an impulse which extends to a con- 
siderable distance; but afterwards, whilst the gland is 
secreting and absorbing, the impulse suffices only to keep 
the same tentacle inflected; though the inflection may last 
for many days. 
If the bending place of a tentacle receives an impulse 
from its own gland, the movement is always towards the 
centre of the leaf; and soit is with all the tentacles, when 
their glands are excited by immersion in a proper fluid. 
The short ones in the middle part of the disc must. be 
excepted, as these do not bend at all when thus excited. On 
the other hand, when the motor impulse comes from one 
side of the disc, the surrounding tentacles, including the 
short ones in the middle of the disc, all bend with precision 
towards the point of excitement, wherever this may be 
seated. This is in every way a remarkable phenomenon; 
for the leaf falsely appears as if endowed with the senses of 
an animal. It is all the more remarkable, as when the 
motor impulse strikes the base of a tentacle obliquely with 
respect to its flattened surface, the contraction of the cells 
must be confined to one, two, or a very few rows at one end. 
And different sides of the surrounding tentacles must tbe 
acted on, in order that all should bend with precision to the 
point of excitement. 
The motor impulse, as it spreads from one or more glands 
across the disc, enters the bases of the surrounding tentacles, 
and immediately acts on the bending place. It does not in 
the first place proceed up the tentacles to the glands, 
exciting them to reflect back an impulse to their bases. 
Nevertheless, some influence is sent up to the glands, as 
their secretion is soon increased and rendered acid; and 
