216 



give out caloric enough to be sensible to the ther- 

 mometer *. This experiment we repeated, by con- 

 fining several snails in a pint jar of air, from the top 

 of which a small thermometer was suspended, and 

 at the bottom a glass of lime-water was placed. 4- 

 film of carbonate of lime soon overspread the lime- 

 water, the inside of the jar was dimmed by moisture, 

 and the mercury in the thermometer rose at the 

 same time nearly one degree. Dr Martine says, that 

 from the result of several trials which he made, 

 snails were about two degrees warmer than the air ! 

 Mr Hunter found the lungs of snails 38, when the 

 atmosphere was 34 ; and, in other instances, snails 

 were six and seven degrees above the atmosphere, 

 when it was so low as 30. Earth worms he found 

 58.5, when the atmosphere was 56 ; and, in other 

 trials, the worms exceeded by four, leeches by three, 

 and slugs by four degrees the temperature of the 

 ambient air {. The temperature of a snail, which 

 was 44, sank, on exposure to a cold mixture, down 

 to 31, and then froze; and several leeches froze 

 likewise when reduced to 31 . In all these expe- 

 riments, the animals, when thawed, were found to be 

 d ad ; but Mr Carlisle says, that the garden snail 

 may be frozen, during its state of dormancy, with- 

 out destroying its muscular irritability (j. 



* Memoirs on Respiration, p. 255. 258. 



f On Thermometers, p. 141. 



f Treatise on the Blood, p. 298. et seq. 



Observations on the Animal (Economy, p. 105. 



(j Philosophical Transactions, 1805, p. 18. 



