28 WHAT IS DARWINISM? 



the primordial germ began to live, it began to 

 grow, to fashion organs however simple, for its 

 nourishment and increase, and for the repro- 

 duction, in some way, of living forms like it- 

 self. How all living things on earth, including 

 the endless variety of plants, and all the diver- 

 sity of animals — insects, fishes, birds, the 

 ichthyosaurus, the mastodon, the mammoth, 

 and man — have descended from the primor- 

 dial animalcule, he thinks, may be accounted 

 for by the operation of the following natural 

 laws, viz. : — 



First, the law of Heredity, or that by which 

 like begets like. The offspring are like the 

 parent. 



Second, the law of Variation, that is, while 

 the offspring are, in all essential characteristics, 

 like their immediate progenitor, they never- 

 theless vary more or less within narrow limits, 

 from their parent and from each other. Some 

 o^ these variations are indifferent, some dete- 

 riorations, some improvements, that is, they are 

 such as enable the plant or animal to exercise 

 its functions to greater advantage. 



Third, the law of Over Production. All 

 plants and animals tend to increase in a geo- 

 metrical ratio ; and therefore tend to overrun 



