58 THE FUNCTIONS OF LIFE. 



In treating of the particular functions of the 

 animal and vegetable economy I shall follow a 

 different order from that in which I have pre- 

 sented them in the preceding sketch. As the 

 Mechanical functions depend upon the simpler 

 properties of matter and the well known laws of 

 mechanism, I think it best to commence with the 

 examination of these. Our attention will next 

 be directed to the highly interesting subjects 

 which relate to the Nutritive or Vital functions 

 both of vegetable and animal structures : for as 

 they involve the chemical properties of organized 

 substances, and are, therefore, of a more refined 

 and intricate nature than the preceding, I 

 conceive they will be best understood after the 

 general mechanism of the frame has been ex- 

 plained. These studies will prepare us for the 

 consideration of living animals as sentient and 

 active beings, endowed by their bounteous Crea- 

 tor with the exalted faculties of perception and 

 of volition, which alone give value to existence, 

 and which raise them so far above the level of 

 the vegetable world. I shall lastly give a very 

 brief account of the reproductive functions, and 

 of the phenomena of animal developement, in 

 which the discoveries of modern times have re- 

 vealed to us so considerable a portion of those 

 extensive plans which an all-wise providence 

 has beneficently devised for the general welfare 

 of animated beings. 



