clasped on all sides. We shall hereafter see what excessively small
doses of certain organic fluids and saline solutions cause strongly
marked inflection.

Whether insects alight on the leaves by mere chance, as a resting
place, or are attracted by the odour of the secretion, I know not. I
suspect from the number of insects caught by the English species of
Drosera, and from what I have observed with some exotic species kept in
my greenhouse, that the odour is attractive. In this latter case the
leaves may be compared with a baited trap; in the former case with a
trap laid in a run frequented by game, but without any bait.

That the glands possess the power of absorption, is shown by their
almost instantaneously becoming dark-coloured when given a minute
quantity of carbonate of ammonia; the change of colour being chiefly or
exclusively due to the rapid aggregation of their contents. When
certain other fluids are added, they become pale-coloured. Their power
of absorption is, however, best shown by the widely different results
which follow, from placing drops of various nitrogenous and
non-nitrogenous fluids of the same density on the glands of the disc,
or on a single marginal gland; and likewise by the very different
lengths of time during which the tentacles remain inflected over
objects, which yield or do not yield soluble nitrogenous matter. This
same conclusion might indeed have been inferred from the structure and
movements of the leaves, which are so admirably adapted for capturing
insects.

The absorption of animal matter from captured insects explains how
Drosera can flourish in extremely poor peaty soil,--in some cases where
nothing but [page 18] sphagnum moss grows, and mosses depend altogether