THE TRIUMPH OF THE MAMMALS 95 



nearly said forefathers. But when the eggs were laid, 

 the mother had a nest ready for them, perhaps 

 underground, to keep them warm. 



This is the same as the birds, you may exclaim! 

 No; because when the little animals came from the 

 eggs the mother fed them from her own breast. The 

 flesh and skin of her breast were perforated, or had a 

 ntunber of large pores in them. When the young 

 licked this part of her breast, the fat-cells from her 

 blood oozed through, and the young were nourished. 

 It was the primitive milk. I need not point out the 

 great importance of this change, and the corresponding 

 change made by the bird. All animals had hitherto 

 been strict individualists. There were, it is true, 

 social groups of corals and sponges and a few others; 

 but these have no consciousness at all of their 

 "socialism." All parents among the higher animals 

 were purely selfish, and took no care of their eggs or 

 young. There was no need. Mother earth provided 

 everything. From this time onward there is at least 

 a link of mother and young, a beginning of social 

 emotion. You see what an Ice Age can do ! 



But how do we know all this if, as I said, the Per- 

 mian Ice Age was at least nine or ten million years 

 ago? Even if we had found a fossil, like that of the 

 "Early Bird," we could not possibly infer from it half 

 of what I have described. It is true that we could 

 not from the bones alone. Some writers credit men 

 of science with almost magical powers. There is a 



