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, terrestrial animal.  Then, secondly, in the adult frog or toad, the naturalist would point to the importance of the skin as not only supplementing, but, in some cases, actually supplanting the work of the lungs as the breathing organ.  Frogs and toads will live for months under water, and will survive the excision of the lungs for like periods; the skin in such cases serving as the breathing surface.  A third point worthy of remembrance is included in the facts just related, and is implied in the information that these animals can exist for long periods without food, and with but a limited supply of air.  We can understand this toleration on the part of these animals when we take into consideration their cold-blooded habits, which do not necessitate, and which are not accompanied by, the amount of vital activity we are accustomed to note in higher animals.  And, as a last feature in the purely scientific history of the frogs and toads, it may be remarked that these animals are known