Cuar. X.] TRANSMISSION OF MOTOR IMPULSE. T99 
experiments, not to mention the six or seven previous ones, 
that the motor impulse is transmitted from any single gland 
or small group of glands through the blade to the other ten- 
tacles more readily and effectually in a longitudinal than in 
a transverse direction. 
As long as the glands remain excited, and this may last 
for many days, even for eleven, as when in contact with 
phosphate of lime, they continue to transmit a motor impulse 
to the basal and bending parts of their own pedicels, for other- 
wise they would re-expand. The great difference in the 
length of time during which tentacles remain inflected over 
inorganic objects, and over objects of the same size containing 
soluble nitrogenous matter, proves the same fact. But the 
intensity of the impulse transmitted from an excited gland, 
which has begun to pour forth its acid secretion and is at the 
same time absorbing, seems to be very small compared with 
that which it transmits when first excited. Thus, when 
moderately large bits of meat were placed on one side of the 
disc, and the discal and submarginal tentacles on the opposite 
side became inflected, so that their glands at last touched the 
meat and absorbed matter from it, they did not transmit any 
motor influence to the exterior rows of tentacles on the same 
side, for these never became inflected. If, however, meat 
had been placed on the glands of these same tentacles before 
they had begun to secrete copiously and to absorb, they un- 
doubtedly would have affected the exterior rows. Neverthe- 
less, when I gave some phosphate of lime, which is a most 
powerful stimulant, to several submarginal tentacles already 
considerably inflected, but not yet in contact with some 
phosphate previously placed on two glands in the centre 
of the disc, the exterior tentacles on the same side were 
acted on. 
„When a gland is first excited, the motor impulse is dis- 
charged within a few seconds, as we know from the bending 
of the tentacle ; and it appears to be discharged at first with 
much greater force than afterwards. Thus, in the case above 
given of a small fly naturally caught by a few glands on one 
side of a leaf, an impulse was slowly transmitted from them 
across the whole breadth of the leaf, causing the opposite 
tentacles to be temporarily inflected, but the glands which 
remained in contact with the insect, though they continued 
for several days to send an impulse down their own pedicels 
to the bending place, did not prevent the teutacles on the 
02 
