215 



173. We proceed next to speak of the heat of 

 those animals, which, from the low temperature they 

 possess, have been denominated cold-blooded, and 

 this we shall do in the same order in which they 

 have been already considered. With regard to in- 

 sects, Dr Martine observes, that the whole tribe is 

 commonly brought under the class of cold animals. 

 Caterpillars have but a small degree or heat, about a 

 division or two, above that of the air they live in 5 

 but the heat of a swarm of bees raises a thermome- 

 ter buried among them, above 97, a degree of heat 

 nothing inferior to our own *. Some insects, as flies 

 and wasps, can sustain a loss of heat without losing 

 life, but a bee cannot f. Coleopterous insects be- 

 come torpid at 34 : at 36, they move slowly and 

 with difficulty, and, at a lower temperature, their 

 muscles cease to be irritable J. During their state 

 of dormancy, the chrysalides of many insects may 

 be frozen without destroying their power of recover- 

 ing action . 



174. In the class vermes, Spallanzani observes, 

 that when a snail or slug is insulated in a jar of at- 

 mospheric air, a thermometer placed in the jar will 

 continue stationary ; but when several are confined 

 together, the mercury rises one-tenth, one-seventh, 

 and even one-fifth of a degree, and in oxygen gas 

 one-third of a degree ; from which he concludes, 

 that snails and slugs, in decomposing oxygen gas, 



* Martine on Thermometers, p. 140, 141. 



f Hunter's Observations on Animal (Economy, p. 108. 



$ Carlisle Phil. Trans. 1805, p. 25. Ibid. p. 



04 



