ir plausibility under a very commonplace scrutiny, there still
exist cases, reported in an apparently exact and truthful manner, in
which these animals have been alleged to appear from the inner
crevices of rocks after the removal of large masses of the formations.
We shall assume these latter tales to contain a plain, unvarnished
statement of what was observed, and deal with the evidence they
present on this footing.

[Illustration: A TOAD.]

One or two notable examples of such verified tales are related by
Smellie, in his "Philosophy of Natural History." Thus, in the "Memoirs
of the French Academy of Sciences" for 1719, a toad is described as
having been found in the heart of an elm tree; and another is stated
to have been found in the heart of an old oak tree, in 1731, near
Nantz. The condition of the trees is not expressly stated, nor are we
afforded any information regarding the appearance of the
toads--particulars of considerable importance in view of the
suggestions and explanations to be presently brought forward. Smellie
himself, while inclined to be sceptical in regard to the truth or
exactness of many of the tales told of the vitality of toads, regards
the matter as affording food for reflection, since he remarks, "But I
mean not to persuade, for I cannot satisfy myself; all I intend is, to
recommend to those gentlemen who may hereafter chance to see such rare
phenomena, a strict examination of every circumstance that can throw
light upon a subject so dark and mysterious; for the vulgar, ever
inclined to render uncommon appearances still more marvellous, are not
to be trusted."

This author strikes the key-note of the inquiry in his concluding
words, and we shall find that the explanation of the matter really
lies in the clear understanding of what are the probabilities, and
what the actual details, of the cases presented for consideration. We
may firstly, then, glance at a few of the peculiarities of the frogs
and toads, regarded from a zooelogical point of view. As every one
knows, these animals emerge from the egg in the form of little
fish-like "tadpoles," provided with outside gills, which are soon
replaced by inside gills, resembling those of fishes. The hind legs
are next developed, and the fore limbs follow a little later; whilst,
with the development of lungs, and the disappearance of the gills and
tail, the animal leaves the water, and remains for the rest of its
life an air-breathing, terrestri