LETTER XXXVIII. 



INTERNAL ANATOMY AND PHYSIOLOGY 

 OF INSECTS CONTINUED. 



RESPIRATION. 



JLlFE 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 a ." 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 b . But the microscopic 

 and anatomical observations of Malpighi, Swammerdam 

 and Lyonet, 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 



a Anat. Compar. iv. 296. 



b Plin. Hist. Nat. ft xi. c. 3. Even Aristotle seems to have given 

 into the common opinion. De Respirdt. c. 3, 9. &c. 



