26] many of the other tentacles. We here see clearly that such bodies
as particles of cinder or little balls of paper, after being carried by
the tentacles to the central glands, act very differently from
fragments of flies, in causing the movement of the surrounding
tentacles.

I made, without carefully recording the times of movement, many similar
trials with other substances, such as splinters of white and blue
glass, particles of cork, minute bits of gold-leaf, &c.; and the
proportional number of cases varied much in which the tentacles reached
the centre, or moved only slightly, or not at all. One evening,
particles of glass and cork, rather larger than those usually employed,
were placed on about a dozen glands, and next morning, after 13 hrs.,
every single tentacle had carried its little load to the centre; but
the unusually large size of the particles will account for this result.
In another case 6/7 of the particles of cinder, glass, and thread,
placed on separate glands, were carried towards, or actually to, the
centre; in another case 7/9, in another 7/12, and in the last case only
7/26 were thus carried inwards, the small proportion being here due, at
least in part, to the leaves being rather old and inactive.
Occasionally a gland, with its light load, could be seen through a
strong lens to move an extremely short distance and then stop; this was
especially apt to occur when excessively minute particles, much less
than those of which the measurements will be immediately given, were
placed on glands; so that we here have nearly the limit of any action.

I was so much surprised at the smallness of the particles which caused
the tentacles to become greatly inflected that it seemed worth while
carefully to ascertain how minute a particle would plainly act. [page
27] Accordingly measured lengths of a narrow strip of blotting paper,