LETTER XXXVIII. 
INTERNAL ANATOMY AND PHYSIOLOGY 
OF INSECTS CONTINUED. 
RESPIRATION. 
“ LIFE and flame have this in common,” says Cuvier, 
‘‘ that neither the one nor the other can subsist without 
air; all living beings, from man to the most minute ve- 
getable, perish when they are utterly deprived of that 
fluid*.” The ancients; however, not perceiving insects 
to be furnished with any thing resembling lungs, took it 
for granted that they did not breathe; though Pliny 
seems to hesitate on the subject”. But the microscopic 
and anatomical observations of Malpighi, Swammerdam 
and Lyonnet, and the experiments of more modern phy 
siologists, have incontestably proved that insects are pro- 
vided with respiratory organs, and that the respiration 
of air is as necessary to them as to other animals. They 
can exist indeed for a time in irrespirable air; and im- 
mersion in hydrogen or carbonic acid gases is not, as I 
have often ascertained, so instantly fatal to them as it 
would be to vertebrate animals; but like them, they 
* Anat. Compar. iv. 296. 
> Plin. Hist. Nat. 1. xi. c. 3. Even Aristotle seems to have given 
into the common opinion. De Respirat. c. 3, 9. &c. 
