510 PHILOSOPHICAL TRANSACTIONS. [aNNO iS/O. 



some of them would sometimes appear to make some use of them, but not 

 enough to sustain themselves, or to keep their falls from being violent. 



The Twentieth Title. 



Of the Necessity of Air to the Motion of such small Creatures as Ants, and even 



Mites themselves. 



In the experiments hitherto mentioned, the animals on which the trials have 

 been made, were several of them of a moderate bulk, and others, though small, 

 yet not the least that nature afforded us. Wherefore I thought fit to annex the 

 following experiment, wherein I designed to examine, whether even those mi - 

 nute sorts of animals, whose bulk is thought the most contemptible, have not 

 as well as the greater need of the air, if not to make them live, yet at least to 

 enable them to move. 



A number of ants were included in a small portable receiver exhausted yester- 

 day about noon : between six and seven in the afternoon they seemed to be all 

 quite dead, and the rather, because though they were very lively just before they 

 were sealed up, running briskly up and down the bubble they were in, yet they 

 grew almost motionless as soon as the air was exhausted ; and a little while after 

 appeared more so; though I then suspected more than I since did, that they 

 were much inconvenienced by some small glutinous substance that seemed to 

 have got into the small receiver from the vapours of the cement. When I 

 looked on them at the time lately mentioned, I opened the glass, whereupon 

 the air rushed in ; but no sign of life appeared for a great while in any of the 

 ants; but looking upon them this morning about nine o'clock, I found many of 

 them alive and moving to and fro. 



It is said by naturalists, upon the authority of Aristotle, that the animal the 

 Greeks called a.%a.ii is the minutest of living creatures. But those of this sort 

 being very hard, if at all to be met with here, I thought fit to make some ex- 

 periments upon the least of the terrestrial animals I could procure, and try whe- 

 ther or no mites themselves, which are reputed but living points, and not to 

 be taken notice of by the naked eye to be living, but by motions which even an 

 attentive one can scarcely discover, stand in need of the air; especially because in 

 case they do, it may suggest to us some odd reflections upon the strange subtlety 

 and minuteness of the aerial particles, which must be capable of flowing in and 

 passing out at the invisible and almost unimaginable small pores and other cavi- 

 ties of the parts of an animal, whose entire body is reputed but a physical point. 



We conveyed then a number of mites, together with the mouldy cheese they 

 were bred in to nourish them, into three or four portable receivers (which werQ 



