"Besides the Toads inclosed in wood and stone, four others were placed each in a small basin of plaster of Paris, four inches deep and five inches in diameter, having a cover of the same material carefully luted round with clay; these were buried at the same time and in the same place with the blocks of stone, and on being examined at the same time with them in December 1826, two of the Toads were dead, the other two alive, but much emaciated. We can only collect from this experiment, that a thin plate of plaster of Paris is permeable to air in a sufficient degree to maintain the life of a Toad for thirteen months.
"In the 19th Vol., No. I, p. 167, of Sillimans American Journal of Science and Arts, David Thomas, Esq. has published some observations on Frogs and Toads in stone and solid earth, enumerating several authentic and well-attested cases. These, however, amount to no more than a repetition of the facts so often stated and admitted to be true, viz., that torpid reptiles occur in cavities of stone, and at the depth of many feet in soil and earth; but they state not anything to disprove the possibility of a small aperture, by which these cavities may have had communication with the external surface, and insects have been admitted.
"The attention of the discoverer is always directed more to the Toad than to the minutiæ of the state of the cavity in which it was contained."
The importance of these experiments, the care with which they were instituted, the deserved reputation of the experimenter, and the philosophic character of his inferences, will, I trust, apologise for the extent of this quotation. I do not think, however, that the question is settled by them; and I will venture to make one or two comments on the facts and on the observations.
Dr Buckland allows that the circumstances of the incarceration of his Toads were not natural. This seems to me an element of more importance than he attributes to it. They were shut up while in active life, after having been confined for two months on scanty food;—"So that they were in an unhealthy and somewhat meagre state at the time of their imprisonment." We do not know what conditions, what natural provisions precede torpidity and are essential to it; but possibly there are some, which in these cases were compulsorily precluded by human interference. It is stated that the animals that survived to the second year were always found awake when examined,—"never in a state of torpor." But Toads that had hid themselves would have been torpid during the winter months; and thus we have a sufficient proof that a natural condition of body had been by some means prevented. The experiment would be much more fair to the Toad, and much more conclusive to me, if the animal were inclosed during the depth of its winter-sleep, care being taken to handle it as little as possible.
As it was, however, most of the Toads inclosed in the limestone survived upwards of thirteen months. This surely is a very remarkable fact. Take the case of No. 9. Here was a Toad, nearly full grown, which had been shut up in a stone cell, covered with a plate of glass carefully luted down all round, so as to exclude air, buried under three feet of earth, so as to exclude the smallest gleam of light; yet, at the expiration of thirteen months, the cell being examined in winter, when normally all Toads ought to be sound asleep, this Toad was wide awake, not in the least emaciated, but so thriving in its strange dungeon as actually to have made 128 grains of flesh! to have actually increased in weight at the rate of 12½ per cent.!
Dr Buckland says, "It is probable there was some aperture in the luting by which small insects found admission." But this is altogether a petitio principii: it absolutely begs the question at issue. Are not these 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 fœcal 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 so abnormal.
No one supposes that incarceration in solid rock is an ordinary event in the life of even a Toad. However it occur,—granting that it may occur,—it must surely be a rare accident happening to an individual here and there, from which millions of Toads are exempt. We may reasonably suppose, too, that not one in a hundred so accidentally incarcerated would survive, the accident in the majority of cases proving fatal. If we bear in mind these not unreasonable presumptions, we shall not hastily decide that all the recorded discoveries of Toads immured are proved false and impossible, because we have not succeeded in finding a case of longevity out of four-and-twenty Toads, many of them little ones, which we took and violently immured at our pleasure.