AND CLASSIFICATION. 21 
which he has included all animal structures. 
And this method, so prolific in his hands, has 
also a lesson for us all. In this country there 
is a growing interest in the study of Nature ; 
but while there exist hundreds of elementary 
works illustrating the native animals of Europe, 
there are few such books here to satisfy the de- 
mand for information respecting the animals of 
our land and water. We are thus forced to 
turn more and more to our own investigations 
and less to authority; and the true method of 
obtaining independent knowledge is this very 
method of Cuvier’s, — comparison. 
Let us make the most common application of 
it to natural objects. Suppose we see together 
a Dog, a Cat, a Bear, a Horse, a Cow, and a 
Deer. The first feature that strikes us as com- 
mon to any two of them is the horn in the Cow 
and Deer. But how shall we associate either of 
the others with these? We examine the teeth, 
and find those of the Dog, the Cat, and the Bear 
sharp and cutting, while those of the Cow, the 
Deer, and the’ Horse have flat surfaces, adapted 
to grinding and chewing, rather than cutting 
and tearing. We compare these features of 
their structure with the habits of these animals, 
and find that the first are carnivorous, that they 
seize and tear their prey, while the others are 
herbivorous or grazing animals, living only on 
