MAMMALIA. 
7 
according to the medium in which the Mammalia live, and 
according to their size and strength. 
Of all the animals, the Mammalia are those which show the 
greatest intelligence ; but this intelligence varies much according 
to the different animals. It is, above all, applied to the necessity 
of self-preservation, the search for food, and the reproduction 
of their species. This faculty shows itself equally in many other 
cases, which we shall have to point out in detail in the sequel of 
this volume. 
Nature has provided with admirable care and an infinite provi- 
dence for all the wants of the Mammalia. To the animal of a 
mild and peaceable character, to which fighting and struggling 
against too redoubtable adversaries is forbidden, she has provided 
the means of avoiding and escaping from its enemies. Some are 
marvellously organized for running, as the Hare and the Gazelle. 
Others hide themselves in subterranean retreats, which serve them 
at the same time as barns, in which to preserve their provisions 
against the winter : such are the Rat, the Marmot, &c. Others, 
Kke the Armadillo, present to their adversaries an invulnerable 
cuirass. Some, erecting their bristles, present to the enemy a 
forest of spikes. There is not one animal, however weak it may 
be, which has not its artifices and means of defence against its 
most terrible enemies. If it were otherwise, all of those feeble 
creatures would have been soon exterminated. 
Man has reduced to a state of domestication, and has subjugated 
to his will, so as to make of them useful assistants in his labours, 
sundry races of Mammalia. In the state of domesticity the 
animal undergoes a physical transformation, and its descendants 
become still more modified. We shall have to insist particularly, 
in this volume, on the manners and habits of domestic animals. The 
classification of the Mammalia which will be followed in this work 
is that of Cuvier, modified by the discoveries and observations of 
subsequent naturalists. True to our plan of exposition, we shall 
arrange the Mammalia according to the degree of the state of 
perfection of their organism. 
We will begin with those singular beings which hold the 
middle place between Birds, Fishes, and Mammalia, which are 
called Ornithorhynchince and Echidnce , and of which De Blainville 
rightly made a separate order, under the name of Monotremata. 
