smaller angle with the footstalk than it did before. This appears at
first sight a distinct kind of movement, but it results from the
incurvation of that part of the margin which is attached to the
footstalk, causing the blade, as a whole, to curve or move upwards.

The length of time during which the tentacles as [page 13] well as the
blade remain inflected over an object placed on the disc, depends on
various circumstances; namely on the vigour and age of the leaf, and,
according to Dr. Nitschke, on the temperature, for during cold weather
when the leaves are inactive, they re-expand at an earlier period than
when the weather is warm. But the nature of the object is by far the
most important circumstance; I have repeatedly found that the tentacles
remain clasped for a much longer average time over objects which yield
soluble nitrogenous matter than over those, whether organic or
inorganic, which yield no such matter. After a period varying from one
to seven days, the tentacles and blade re-expand, and are then ready to
act again. I have seen the same leaf inflected three successive times
over insects placed on the disc; and it would probably have acted a
greater number of times.

The secretion from the glands is extremely viscid, so that it can be
drawn out into long threads. It appears colourless, but stains little
balls of paper pale pink. An object of any kind placed on a gland
always causes it, as I believe, to secrete more freely; but the mere
presence of the object renders this difficult to ascertain. In some
cases, however, the effect was strongly marked, as when particles of
sugar were added; but the result in this case is probably due merely to
exosmose. Particles of carbonate and phosphate of ammonia and of some
other salts, for instance sulphate of zinc, likewise increase the
secretion. Immersion in a solution of one part of chloride of gold, or