OF NATURAL HISTORY. 125 



the whole body to the external air for half an hour, the powers of 

 life completely returned. After fufpending the caterpillar about 

 two hours with the laft five pair of ftigmata above the furface, he 

 found that life was not extinguifhed. He then raifed the water till 

 the anus and laft pair of ftigmata only were expofed to the atmof- 

 phere. He allowed the caterpillar to remain in this fituation more 

 than half an hour ; and he obferved that it often bended its body 

 with a view to reach the furface, and that, during thefe efforts, bub- 

 bles of air iflued from the anterior, but not from the pofterior ftig- 

 mata. He likewlfe remarked, that, on the fmalleft motion of the 

 animal, thefe bubbles were difcharged, but that they were augment- 

 ed both in quantity and fize, in proportion to the agitations of the 

 body. M. Bonnet immediately raifed the water till it covered the 

 two laft ftigmata ; the caterpillar was violently agitated ; but no 

 bubbles of air, the communication being cut off, appeared, and all 

 motion ceafed. He inftantly lowered the water, and expofed the 

 two pofterior ftigmata to the air ; the animal refumed its move- 

 ments ; but in a moment after it expired. By another experiment, 

 M. Bonnet difcovered that a caterpillar lived eight days fufpended 

 in water, during all which time it breathed folely by the two pofte- 

 rior ftigmata. 



After thefe, and many other fads of a fimilar kind, which de- 

 monftrate that air is neceflary for the fupport and continuation of 

 animal life, it fliall only be remarked, that, when caterpillars under- 

 go their laft change, and appear in the form of flies of every deno- 

 mination, Nature has ftill furniflied them with ftigmata, or refpira- 

 tory organs. 



Reptiles of all kinds are likewife furnifhed with organs of refpi- 

 ration. Land-fnails, at the approach of winter, bury themfelves in 

 the earth, or retire into holes of rocks, or of old buildings, where 



they 



