THE FUNCTIONS OF LIFE. 39 



ultimate ends of animal existence, and which 

 are emphatically termed the Animal Functions. 



The vital as well as the animal functions 

 require for the execution of their various objects 

 certain instruments of an appropriate mecha- 

 nical construction, adapted to those objects. To 

 the contrivances of the mechanist must be added 

 a refined hydraulic apparatus for the conveyance 

 of fluids, and for the regulation of their move- 

 ments ; and with these must be conjoined the 

 skilful combinations of the laboratory, by which 

 the powers of the most subtle chemistry are 

 exercised in effecting all the transmutations re- 

 quired by this elaborate system of operations. 

 As far as they involve mechanical principles, 

 these objects again arrange themselves under 

 the mechanical functions : and I shall accordingly 

 include them under that head, when giving an 

 account of this branch of the subject. 



There is another, and a most important conse- 

 quence that flows from the peculiar chemical 

 conditions of the materials of which animal 

 structures are composed. The mode in which 

 their elements are combined is so complex as 

 to require a long and elaborate process to ac- 

 complish that purpose ; and neither the organs 

 with which animals are furnished, nor the powers 

 with which those organs are endowed, are ade- 

 quate to the conversion of the materials furnished 

 by the inorganic world into the substances re- 



