ON THE DIGESTIVE FUNCTION, ETC. 



Air alone appears sufficient for the support of animals of other kinds. 

 Snails and chameleons have been known repeatedly to live upon nothing 

 else for years.* Garman asserts that it is a sufficient food for spiders ; 

 and that though they will devour other food, as fishes will that may be 

 maintained alone on water, they do not stand in need of any other. La- 

 treille confirms this assertion to a considerable extent, by informing us that 

 he stuck a spider to a piece of cork, and precluded it from communication 

 with any thing else for four successive months, at the end of which time it 

 appeared to be as lively as ever.j And Mr. Baker tells us, in the Philo- 

 sophical Transactions, that he had a beetle that lived in a glass confine- 

 ment for three years without food, and then fled away by accident. 



The larves of ants, as well as of several other insects of prey, are not 

 only supported by air, but actually increase in bulk, and undergo their 

 metamorphoses without any other nourishmenti. It is probable, also, that 

 air is at times the only food of the scolopendra phoAphorea^ or luminous 

 centipede, which has been seen illuminating the atmosphere, and some- 

 times falhng into a ship, a thousand miles from land. 



Amphibious animals have a peculiar tenacity to life under every circum- 

 stance of privation ; and not only frogs, and toads, but tortoises, lizards, and 

 serpents, are well known to have existed for months, and even years, with- 

 out other food than water — in some instances, without other food than air. 



Mr. Bruce kept two cerastes, or horned snakes, in a glass jar for two years, 

 without giving them any thing. He did not observe that they slept in the 

 winter-season ; and they cast their skins, as usual, on the last day of April. J 



Lizards, and especially the newt species, have been found imbedded in 

 a chalk-rock, apparently dead and fossilized, but have re-assumed hving 

 action on exposure to the atmosphere. § On their detection in this state 

 the mouth is usually closed with a glutinous substance, and closed so te- 

 naciously, that they often die of suffocation in the very effort to extricate 

 themselves from this material. 11 ^ 



In respect to toads the same fact has been ascertained, for nearly two 

 years, by way of experiment ;ir and has been verified, by accident, for a 

 much longer term of time. The late Edward Walker, Esq. of Guesting- 

 thorpe, Essex, informed me not long since, that he had found a toad perfectly 

 alive in the midst of a full grown elm, after it was cut down by his order, 

 exactly occupying the cavity which it appeared gradually to have scooped 

 out as it grew in size, and which had not the smallest external communi- 

 cation by any aperture that could be traced. And very explicit, and ap^ 

 parently very cautious, accounts have been repeatedly published in dif- 

 ferent journals, of their having been found alive, imbedded in the very | 

 middle of trunks of trees and blocks of marble, so large and massy, that, | 

 if the accounts be true, they must have been in such situations for at least h 

 a century,** There is a very particular case of this kind given by M, i 

 Seigue, in the Memoirs of the Royal Academy of Paris.tt 



* Encyclop. Brit. art. Physiol, p. 679. t Monthly Rev. Appx. Iv. 494. 



X Voyages, Appendix, p. 296. Svo. edit. § Wilkinson, Tilloch*s Phil. Mag. Dec. 1816. 



II Journ. of Science, No. XIl. p. 375. 



i! See Dalyell's Introd. to his Translation of Spalanzani's Tracts, p. xliii. 1803. 

 See various instances, Encycl. Brit. art. Physiol, p. 681. 



tt Mem. 1731. H. 24. Dr. Edwards, of Paris, has sufficiently ascertained of late, that 

 blocks of mortar, and heaps of sand, are porous enough to admit so much air as is requisite to 

 support the life of lizards, toads, and other amphibials of the batrachian family ; but that they 

 all perish if surrounded by mercury, or even water, so as to intercept the air by their being 

 encompassed by an exhaustet^ receiver. In boxes of mortar or sand, however, they live much 

 longer than in boxes plunged under water. The probable cause is, that the air of the atmos- 



