ese insects entirely gratuitous? The luting was, of course, carefully
laid on: there could be no drying to cause contraction, buried as it was
in the earth; the glass was uninjured; no orifice was detected; and yet,
forsooth, it must be assumed that "small insects found admission." Then,
too, consider the problem. It is not the possibility that a
microscopically minute insect or two may have managed in some
inscrutable way to insinuate themselves, but insects sufficient to
support this large Toad for thirteen months, and to make it at the end
of that time 128 grains heavier than it was when first inclosed! There
is the fact, as stated by this careful observer; and I am sure his
hypothesis of intrusive insects will not account for it.

I might make similar remarks on No. 5. The glass was "_slightly_
cracked." No insects were discovered in it; nor is any perceptible
orifice alluded to; yet this Toad had increased from 1185 grains to 1265
grains. The "_slight_ crack" in the glass makes this example less
remarkable at first sight than the other; but in reality it is equally
inscrutable. Insects, however minute, do not pass through glass merely
cracked; but the requirement is the admission of insects enough to make
an increase of flesh of 80 grains' weight, besides maintaining the waste
of the Toad during thirteen months. Where, in each case, was the
excrement corresponding to such an augmentation? An insect-diet, as
every naturalist knows, leaves a very considerable residuum of
indigestible, incorruptible, chitinous matter: the f{oe}cal remains of
an insect-diet sufficient to keep an adult Toad in condition for
thirteen months, and leave him 128 grains heavier than at first, would
form no inconsiderable or inconspicuous mass. Yet the silence of the
observer on so conclusive an evidence proves that it was utterly
wanting.

The Toads which survived longest were the largest specimens. Perhaps it
requires a condition of peculiar vigour to bear the incarceration. Even
these were all dead before two years had elapsed. But then it must be
remembered that they had been disturbed: they had been taken out,
handled, and weighed, and replaced; and during the second year they had
been examined "several times." Air, it is true, was not admitted in
these later examinations; but _light was_; and it may be that the
absence of all external stimulus (and light is a potent one) is
indispensable to the prolongation of vitality under conditions