The Romance of Natural History, Second Series

by Philip Henry Gosse

"When they were first examined in December 1826, not only were all the small Toads dead, but the larger ones appeared much emaciated, with the two exceptions above mentioned; we have already stated that these probably owed their increased weight to the insects which had found access to the cells, and become their food.

"The death of every individual of every size in the smaller cells of compact sandstone, appears to have resulted from a deficiency in the supply of air, in consequence of the smallness of the cells, and the impermeable nature of the stone; the larger volume of air originally inclosed in the cells of the limestone, and the porous nature of the stone itself, (permeable as it is slowly by water, and probably by air,) seem to have favoured the duration of life to the animals inclosed in them without food.

"It should be noticed that there is a defect in these experiments, arising from the treatment of the twenty-four Toads before they were inclosed in the blocks of stone. They were shut up and buried on the 26th of November, but the greater number of them had been caught more than two months before that time, and had been imprisoned all together in a cucumber frame placed on common garden earth, where the supply of food to so many individuals was probably scanty, and their confinement unnatural, so that they were in an unhealthy and somewhat meagre state at the time of their imprisonment. We can therefore scarcely argue with certainty from the death of all these individuals within two years, as to the duration of life which might have been maintained had they retired spontaneously, and fallen into the torpor of their natural hibernation in good bodily condition.

"The results of our experiments amount to this: all the Toads, both large and small, inclosed in sandstone, and the small Toads in the limestone also, were dead at the end of thirteen months. Before the expiration of the second year all the large ones also were dead; these were examined several times during the second year through the glass covers of the cells, but without removing them to admit air; they appeared always awake, with their eyes open, and never in a state of torpor, their meagreness increasing at each interval in which they were examined, until at length they were found dead; those two also which had gained an accession of weight at the end of the first year, and were then carefully closed up again, were emaciated and dead before the expiration of the second year.

"At the same time that these Toads were inclosed in stone, four other Toads of middling size were inclosed in three holes, cut for this purpose on the north side of the trunk of an apple-tree; two being placed in the largest cell, and each of the others in a single cell. The cells were nearly circular, about five inches deep and three inches in diameter; they were carefully closed up with a plug of wood, so as to exclude access of insects, and apparently were air-tight; when examined at the end of a year, every one of the Toads was dead, and their bodies were decayed.

"From the fatal result of the experiments made in the small cells cut in the apple-tree and the block of compact sandstone, it seems to follow that Toads cannot live a year excluded totally from atmospheric air; and, from the experiments in the larger cells within the block of oolitic limestone, it seems also probable that they cannot survive two years entirely excluded from food; we may therefore conclude that there is a want of sufficiently minute and accurate observation in those so frequently recorded cases, where Toads are said to be found alive within blocks of stone and wood, in cavities that had no communication whatever with the external air. The fact of my two Toads having increased in weight at the end of the year, notwithstanding the care that was taken to inclose them perfectly by a luting of clay, shews how very small an aperture will admit of insects sufficient to maintain life. In the cell No. 5, where the glass was slightly cracked, the communication though small was obvious, but in the cell No. 9, where the glass cover remained entire, and where it appears certain, from the increased weight of the inclosed animal, that insects must have found admission, we have an example of these minute animals finding their way into a cell to which great care had been taken to prevent any possibility of access.

"Admitting, then, that Toads are occasionally found in cavities of wood and stone with which there is no communication sufficiently large to allow the ingress and egress of the animal inclosed in them, we may, I think, find a solution of such phenomena in the habits of these reptiles, and of the insects which form their food. The first effort of the young Toad, as soon as it has left its tadpole state and emerged from the water, is to seek shelter in holes and crevices of rocks and trees. An individual which, when young, may have thus entered a cavity by some very narrow aperture, would find abundance of food by catching insects, which, like itself, seek shelter within such cavities; and may soon have increased so much in bulk as to render it impossible to get out again through the narrow aperture at which it entered. A small hole of this kind is very likely to be overlooked by common workmen, who are the only people whose operations on stone and wood disclose cavities in the interior of such substances.

"In the case of Toads, Snakes, and Lizards, that occasionally issue from stones that are broken in a quarry, or in sinking wells, and sometimes even from strata of coal at the bottom of a coal-mine, the evidence is never perfect to shew that the reptiles were entirely inclosed in solid rock. No examination is ever made until the reptile is first discovered by the breaking of the mass in which it was contained, and then it is too late to ascertain, without carefully replacing every fragment, (and in no case that I have seen reported has this ever been done,) whether or not there was any hole or crevice by which the animal may have entered the cavity from which it was extracted. Without previous examination it is almost impossible to prove that there was no such communication. In the case of rocks near the surface of the earth, and in stone quarries, reptiles find ready admission to holes and fissures. We have a notorious example of this kind in the Lizard found in a chalk-pit, and brought alive to the late Dr Clark. In the case also of wells and coal-pits, a reptile that had fallen down the well or shaft, and survived its fall, would seek its natural retreat in the first hole or crevice it could find, and the miner dislodging it from this cavity, to which his previous attention had not been called, might in ignorance conclude that the animal was coeval with the stone from which he had extracted it.

"It remains only to consider the case (of which I know not any authenticated example) of Toads that have been said to be found in cavities within blocks of limestone, to which, on careful examination, no access whatever could be discovered, and where the animal was absolutely and entirely closed up with stone. Should any such case ever have existed, it is probable that the communication between this cavity and the external surface had been closed up by stalactitic incrustation, after the animal had become too large to make its escape. A similar explanation may be offered of the much more probable case of a live Toad being entirely surrounded with solid wood. In each case, the animal would have continued to increase in bulk so long as the smallest aperture remained by which air and insects could find admission; it would probably become torpid as soon as this aperture was entirely closed by the accumulation of stalactite or the growth of wood. But it still remains to be ascertained how long this state of torpor may continue under total exclusion from food and from external air: and, although the experiments above recorded shew that life did not extend two years in the case of any one of the individuals which formed the subjects of them, yet, for reasons which have been specified, they are not decisive to shew that a state of torpor, or suspended animation, may not be endured for a much longer time by Toads that are healthy and well fed up to the moment when they are finally cut off from food, and from all direct access of atmospheric air.

"The common experiment of burying a Toad in a flower-pot covered with a tile, is of no value unless the cover be carefully luted to the pot, and the hole at the bottom of the pot also closed, so as to exclude all possible access of air, earthworms, and insects. I have heard of two or three experiments of this kind, in which these precautions have not been taken, and in which at the end of a year the Toads have been found alive and well.