I'll 



CHAP. VI11 



animal Economy, considered, in 



1^ 

 HE sketch I have lately drawn of animal ece* 

 nomy, affords a slight idea of what constitutes the es- 

 sence of life in most animals. We shall now treat of 

 the principal varieties which the organization of different 

 species presents us with. Insects, hitherto little known, 

 exhibit some singularities in this very respect, to which 

 we shall confine ourselves byway of preference, in order 

 to avoid such, details as might carry us to too great a, 

 length. 



We have already seen, in some measure, the different 

 parts contained in the composition of these little ma* 

 chines : we will now contemplate their exercise aad va~ 

 rious effect*. 



2. The mechanism of respiration is very obscure in 

 ifisects : we only know, that in them it differs greatly 

 from that in those animals which are nu>st known to us. 

 But we judge with greater certainty concerning this di- 

 ference by the comparison of the organs, than by that 

 of their exercise. When a drop of greasy liquor is up- 

 plied to one, or several stigmata of ar* insect, tiie cor- 

 responding parts become paralytic : the interception of 

 tiic air in one part is followed by that of liquors, or 

 spirits. When we stop up all the stigmata, the insect 

 dres immediately : if we afterwards open them, we sljaH 

 I arc ei Ye the inside to xevive. The air which then 



