PREFACE. ix 



to the subject that unity of design, and that scientific 

 form, which are generally wanting in books profes- 

 sedly treating of Natural Theology, published prior 

 to the present series ; not excepting even the unri- 

 valled and immortal work of Paley. By furnishing 

 those general principles, on which all accurate and 

 extensive knowledge must substantially be founded, I 

 am not without a hope that this compendium may 

 prove a useful introduction to the study of Natural 

 History; the pursuit of which will be found not only 

 to supply inexhaustible sources of intellectual grati- 

 fication, but also to furnish, to contemplative minds, 

 a rich fountain of religious instruction. To render 

 these benefits generally accessible, I have confined 

 myself to such subjects as are adapted to every class 

 of readers; and, avoiding all unnecessary extension of 

 the field of inquiry, have wholly abstained from en- 

 tering into historical accounts of the progress of dis- 

 covery; contenting myself with an exposition of the 

 present state of the science. I have also scrupulously 

 refrained from treading in the paths, which have been 

 prescribed to the other authors of these treatises; and 

 have accordingly omitted all consideration of the hand, 

 the voice, the chemical theory of digestion, the ha- 

 bits and instincts of animals, and the structures of an- 

 tediluvian races ; the extent of the field which re- 

 mained, and which, with these few exceptions, em- 

 braces nearly the whole of the physiology of the two 

 Vol. I. B 



