28 THE STORY OF ANIMAL LIFE 



istics of the more generalized ancestral type, 

 from which both parents have alike been derived. 



When the ancestral type is in some way in- 

 ferior to the modern one, variation which con- 

 sists in reverting to the former is often referred 

 to as Degeneracy. There is reason to believe 

 that discomfort and hardship of existence tend 

 to produce variation of this kind a fact of 

 supreme importance, when the problem of De- 

 generacy is considered in connection with human 

 life. When creatures begin to degenerate, it is, 

 in fact, as if the species were saying to itself, " I 

 have gone astray ; let me retrace my steps along 

 the road by which I came, and maybe I shall find 

 comfort and safety ; step by step I will try to go 

 back to my ancestral form." 



Very rapid variation of any sort is indeed 

 often a sign that the struggle for existence is too 

 hard for the type in question. The palaeontolo- 

 gist can tell us of types that present numerous 

 variations before becoming extinct; while others, 

 comfortably holding their own in the struggle 

 for existence, remain practically unchanged dur- 

 ing age after age of the geological record, and 

 survive even up to the present day. We may 

 borrow from commercial life a homely illus- 

 tration that will explain this aspect of varia- 

 tion. When competition in trade is keen, the 

 seller must have novelties; he will try all sorts, 

 and find some good, some bad, some indif- 

 ferent. If he now revives an out-of-date pat- 

 tern of goods, for the sole sake of change, this 

 is Degeneracy. But where, on the contrary, com- 

 petition is dull, the same firm will turn out the 

 same goods for a long period of time. There is 

 an optimum in trade competition : a reasonable 



