OF NATURAL KISfOllY. 133 



by the fame orifices, till Bonnet, and, after him, Reaumur, 

 afcertained the fact by many curious and accurate experi- 

 ments. The firft of thefe authors immerfcd numbers of 

 caterpillars, of different kinds, and at different times, in 

 water, and he obferved, both with the naked eye, and by the 

 affilf ance of a glafs, bubbles of air ifTuing from various parts 

 of their bodies, and particularly from the ftigmata. To re- 

 move all deception from his experiments before immerlion, 

 he carefully moiftened the caterpillars with water, in order 

 to diflod^e any portions of the external air that might be ad- 

 hering to their bodies. Some of them he allowed to remain 

 fo long under water, that they had every appearance of death. 

 He then raifed the head and the two anterior fligmata above 

 the furface. The head, and firft pair of legs, foon began to 

 move from fide to fide ; and the body necefTarily partook of 

 the fame motions. During thefe movements, many bubbles 

 of air ifTued from the poilerior and intermediate ftigmata, 

 which ftiil remained under water ; but the membranous limbs 

 continued nearly at reft. He next kept a caterpillar under 

 water till all motion was fufpended. Then he elevated the 

 anus and the two laft ftigmata above the furface, that they 

 might have a communication with the external air. He 

 kept the animal in this fituation about half an hour, without 

 any fymptoms of re-animation. After raifing the body fuc- 

 ceffively from the laft to the firft pair of ftigmata, ftill the 

 animal exhibited no fymptoms of life *, but, when he expof- 

 ed 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 ftigma- 

 ta above the furface, he found that life was not extinguiflied. 

 He then raifed the water till the anus and laft pair of ftigma- 

 ta only were expofed to the atmofphere. 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 



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