longer time over insects than over meat; and from what I have seen, I
can well believe that this is the case, especially if the insects are
large.
In all the above cases, and in many others in which leaves remained
closed for a long but unknown period over insects naturally caught,
they were more or less torpid when they reopened. Generally they were
so torpid during many succeeding days that no excitement of the
filaments caused the least movement. In one instance, however, on the
day after a leaf opened which had clasped a fly, it closed with extreme
slowness when one of its filaments was touched; and although no object
was left enclosed, it was so torpid that it did not re-open for the
second time until 44 hrs. had elapsed. In a second case, a leaf which
had expanded after remaining closed for at least nine days over a fly,
when greatly irritated, moved one alone of its two lobes, and retained
this unusual position for the next two days. A third case offers the
strongest exception which I have observed; a leaf, after remaining
clasped for an unknown time over a fly, opened, and when one of its
filaments was touched, closed, though rather slowly. Dr. Canby, [page
311] who observed in the United States a large number of plants which,
although not in their native site, were probably more vigorous than my
plants, informs me that he has several times known vigorous leaves to
devour their prey several times; but ordinarily twice, or, quite often,
once was enough to render them unserviceable. Mrs. Treat, who
cultivated many plants in New Jersey, also informs me that several
leaves caught successively three insects each, but most of them were
not able to digest the third fly, but died in the attempt. Five leaves,
however, digested each three flies, and closed over the fourth, but
died soon after the fourth capture. Many leaves did not digest even one
large insect. It thus appears that the power of digestion is somewhat
limited, and it is certain that leaves always remain clasped for many
days over an insect, and do not recover their power of closing again
for many subsequent days. In this respect Dionaea differs from Drosera,
which catches and digests many insects after shorter intervals of time.
We are now prepared to understand the use of the marginal spikes, which
form so conspicuous a feature in the appearance of the plant (fig. 12,
p. 287), and which at first seemed to me in my ignorance useless
appendages. From the inward curvature of the lobes as they approach
each other, the tips of the marginal spikes first intercross, and
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