THE CONQUEST OF THE DRY LAND 213 
With the increasing need for protecting the 
young there has grown up an increasing de- 
gree, not only of parental care, but of parental 
affection. The highest expression of this is 
found—if we leave the birds out of account— 
among the Mammals, that great class which 
includes forms so different as Man, the mon- 
keys, the carnivores, the hoofed animals, the 
gnawers, besides the aerial bats and the ma- 
rine whales. All these animals have one great 
point of resemblance to which they owe their 
name of Mammal—the young are fed for the 
first period of their lives on the milk of the 
mother. The period of suckling varies greatly 
in length. The little harvest-mouse, the small- 
est but one of our four-footed beasts, makes an 
egg-shaped nest by splitting stalks of grass or 
corn and weaving them firmly together. The 
nest, which usually hangs from a corn-stalk, 
is lined with soft leaves, and in this comfort- 
able home the young ones, eight or nine at a 
birth, are brought forth, and are suckled by 
the mother. But she only allows them this 
luxurious life for a week or two till they are 
able to see and to stand on their own legs. 
Then, we are told, she takes them out, “ gives 
them a little practical instruction in the art 
