IB FINAL CAUSES. 



prebend the nature of that subtle and pervading 

 principle, by the agency of which all these won- 

 derful phenomena of life are produced, and which, 

 combining into one harmonious system so many 

 heterogeneous and jarring elements, has led to the 

 formation of this exquisite fabric, this elaborate 

 machine, this miraculous assemblage of faculties ? 



The discovery of a clue, if any such can be 

 found, to the mazes of this perplexing labyrinth 

 can be hoped for only from the successful cultiva- 

 tion of the science of physiology. But before 

 engaging in this arduous study, we ought previously 

 to inquire into the methods of reasoning by which 

 it is to be conducted. 



The object of Physiology is, by the diligent ex- 

 amination of the phenomena of life, to ascertain 

 the laws which regulate those phenomena, both as 

 they apply to the individual beings endowed with 

 life, and also as they relate to the various assem- 

 blages that constitute the species, the genera, the 

 families, the orders, and the classes of those beings; 

 and, lastly, as they concern the whole collective 

 union of the organized world. 



These peculiar laws, which it is the province of 

 physiology to investigate, are, as I have before 

 observed, of two kinds, each founded upon rela- 

 tions of a different class. The first, which depend 

 upon the simple relation of cause and effect, are 

 concerned merely with the natural powers of mat- 

 ter. They are the laws that regulate the succession 

 of phenomena purely physical in all their stages. 

 These phenomena consist in changes among mate- 

 rial particles, which are either of a mechanical or 

 chemical nature ; or in the affections of imponder- 



