214 HisTORr or 



poiiils, from tlie want of this necessary to animal existence. 

 Many have been the animals that idle curiosity has tortured in 

 the prison of a receiver, merely to observe the manner of their 

 dying. We shall, from a thousand instances, produce that of 

 the viper, as it is known to be one of the most vivacious rep 

 tiles in the world; and as we shall feel but little compassion 

 for its tortures. Mr Boyle took a new caught viper, and shut- 

 ting it up into a small receiver, began to pump away the air.' 

 " At first, upon the air's being drawn away, it began to swell ; 

 gometime after he had done pumping, it began to gape, 

 and open its jaws; being thus compelled to open its jawj, 

 it once more resumed its former lankness j it then began 

 to move up and down within, as if to seek for air, and aftei 

 a wlaile foamed a little, leaving the foam sticking to the inside 

 of the glass ; soon after, the body and neck grew prodigiously 

 tumid, and a blister appeared upon its back ; an hour and a half 

 after, the receiver was exhausted, the distended viper moved, and 

 gave manifest signs of life ; the jaws remained quite distended; 

 as it were from beneath the epiglottis, came the black tongue, 

 and reached beyond it ; but the animal seemed, by its postiue, 

 not to have any life ; the mouth also was grown blackish with- 

 in ; and in this situation it continued for twenty -three hours. 

 But upon the air being re-admitted, the viper's mouth was pre- 

 sently closed, and soon after opened again ; and for some time 

 those motions continued, which argued the remains of life." 

 Such is the fate of the most insignificant or minute reptile that 

 can be thus included. Mites, fleas, and even the little eels that 

 are found swimming in vinegar, die for want of air. Not only 

 these, but the eggs of these animals will not produce in vacuo, 

 but require air to bring them to perfection. 



As in this mamier air is necessary to their subsistence, so also 

 is must be of a proper kind, and not impregnated with foreign mix- 

 tures. That fictitious air which is pumped from plants or fluids, 

 is generally, in a short time, fatal to them. Mr Boyle has givea 

 us many experiments to this purpose. After having shown 

 that all vegetable and most mineral substances, properly prepai - 

 ed, may afford air, by being placed in an exhausted receiver, and 

 this in such quantities, that some have thought it a new sub- 



1 Boyle's riiysico-Mechan. Exper. passim. 



