128 A HISTORY OF 



the plint or flower thus ceasing to vegetate, is Kept, by being secured 

 from the external air, a much longer time sweet than it would have 

 continued, had it heen openly exposed. 



That air which is so necessary to the life of vegetables, is still more 

 so to that of animals ; there are none found, how seemingly torpid 

 soever, that do not require their needful supply. Fishes themselves 

 will not live in water from whence the air is exhausted ; and it is 

 generally supposed that they die in frozen ponds, from the 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 ob 

 serve 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 viva 

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

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

 up into a small receiver, began to pump away the air.* " At nrst, 

 upon the air's being drawn away, it began to swell ; some time after 

 he had dono pumping, it began to gape, and open its jaws ; being 

 thus compelled to open its jaws, it once more resumed its tormer 

 lankness ; it then began to move up and down within, as if to seek 

 for air, and after a while foamed a little, leaving the foam sticking to 

 the inside of the glass ; soon after the body and neck grew prodigi- 

 ously 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 posture, not to have any 

 life ; the mouth also was grown blackish within ; and in this situation 

 it continued for twenty-three hours. But upon the air's being re-ad- 

 mitted, the viper's mouth was presently 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 re- 

 quire air to bring them to perfection. 



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

 must be of a proper kind, and not impregnated with foreign mixtures. 

 That factitious air which is pumped from plants or fluids, is generally, 

 in a short time, fatal to them. Mr. Boyle has given us many experi- 

 ments to this purpose. After having shewn that all vegetable, and 

 most mineral substances, properly prepared, may afford air, by being 

 placed in an exhausted receiver, and this in such quantities, that some 

 have thought it a new substance, made by the alteration which the 

 mineral or plant has undergone by the texture of its parts being loos- 

 ened in the operation having shewn, I say, that this air may be drawn 

 in great quantities from vegetable, animal, or mineral substances, such 

 as apples, cherries, amber burnt, or hartshornf he included a frog 

 in artificial air, produced from paste ; in seven minutes' space it suf- 



* Boyle's Physico-Mechan. Exper. passim 

 t Boyle's Physico-Mechan. vol. ii. p. 598. 



