BOOK II. 



PHYSIOLOGY OF INSECTS. 



CHAPTER I. 



PHYSIOLOGY OF INSECTS IN GENERAL. 



301. The Physiology of Insects is the account 

 of how they are made : tliere are in every animal 

 four essential elements, — matter, motion, sensation, 

 and mind. 



302. Matter is inert — it does not move by its 

 own powers ; it is tangible — the touch ascertains 

 that it resists : matter in animals has various 

 degrees of consistency ; convenience, however, 

 has suggested its division into solid and fluid. 



303. Matter, chiefly in its solid form, is the 

 element of which the systems of organs are com- 

 posed ; and organs are the instruments by which 

 functions are performed : in all animals there are 

 seven systems of organs to perform seven series 

 of functions. 



