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 otherwise 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 sub-marginal 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 undoubtedly would have affected the exterior rows.  Nevertheless, 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 discharged within a few seconds, as we know from the [page 241] 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 tentacles on the opposite side from quickly re-expanding; so that the motor discharge must at first have been more powerful than afterwards.

When an object of any kind is placed on the disc, and the surrounding tentacles are inflected, their glands secrete more copiously and the secretion becomes acid, so that some influence is sent to them from the discal glands.  This change in the nature and amount of the secretion cannot depend on the bending of the tentacles, as the glands of the short central tentacles secrete acid when an object is placed on them, though they do not themselves bend.  Therefore I inferred that the glands of the disc sent some influence up the surrounding tentacles to their glands, and that these reflected back a motor impulse to their basal