OF NATURAL HISTORY. %$$ 



«atIon with the external air, the animal, to remedy the evil, 

 makes a fmall aperture in its cover. In this ftate fnails re- 

 main fix or feven months, without food or motion, till the 

 genial warmth of the fpring breaks their flumber, and calls 

 forth their active powers. Hence it fhould appear, that air is 

 more neceflary to the prefervation of animal life than food 

 itfelf ; for, in numberlefs inftances, animals can live, not for 

 days or weeks, but for months, without fupplies of nour- 

 ifliment. None of them, however, are capable of exifting 

 nearly fo long without having fome communication with 

 the air. 



With regard to fnails that live in frefh waters, or in the 

 ocean, the fpecies of which are numerous, their manner of 

 refpiring is lingular. All of them have an aperture on the 

 right fide of the neck. This aperture ferves the complicat- 

 ied purpofes of difcharging the faeces, of lodging the organs 

 of generation, of afcending and defcending in the water, 

 and of refpiration. They are frequently obferved to fi:rait- 

 pn the orifice of this aperture, to ftretch it out in the form 

 of an oblong tube ; and, in this {late, they rife to the fur- 

 face, in order to expel the former air, and take in a new 

 fupply. 



But, though air feems to be an indifpenfible principle of 

 animal life, yet many animals can live longer without the ufe 

 of this element, or at leaft with fmaller quantities of it, than 

 others. Even men, by long pradlice, acquire the faculty of 

 retaining the air in their lungs for an almoft incredible length 

 of time. Some of thofe wretched creatures who are com- 

 pelled by tyranny to dive for pearl-oyfters, have been known 

 to continue under water three quarters of an hour without 

 receiving a frefh fupply of air. Thofe animals which lie 

 torpid during the winter, as the hedge-hog, the 4ormoufe, 

 the marmot, &c. though perhaps not entirely deprived of all 

 communication with the air, exift, without any apparent 



