106 STUDY OF NATURAL HISTORY. 
But the question resolves itself into this, Are there 
any fixed and universal laws by which the variations 
of the forms of nature are regulated? If this question 
can be answered in the afhrmative; if all these 
variations can be traced to certain primary types, 
following each other in one constant and unchanging 
series, we have the most conclusive evidence that 
human research can elicit. It will be our especial 
object, therefore, in the subsequent volumes of this _ 
work, to demonstrate the truth of this proposition, 
appealing for its stability to those facts with which 
we first commence the fabric of the science, and 
which, coming within the range of ordinary observ- 
ation, it will be in the power of every one to verify 
or disprove. 
PR oe 
