8 EVOLUTION AND ANIMAL LIFE 



as something which is beyond modification, unchanging so long 

 as it exists. 



"I believe/ 7 said the rose to the lily in the parable, "that 

 our gardener is immortal. I have watched him from day to 

 day since I bloomed, and I see no change in him. The tulip 

 who died yesterday told me the same thing." 



As a flash of lightning in the duration of the night, so is the 

 life of man in the duration of nature. When one looks out on 

 a storm at night he sees for an instant the landscape illumined 

 by the lightning flash. All seems at rest. The branches in the 

 wind, the flying clouds, the falling rain, are all motionless in 

 this instantaneous view. The record on the retina takes no 

 account of change, and to the eye the change does not exist. 

 Brief as the lightning flash in the storm is the life of man com- 

 pared with the great time record of life upon earth. To the 

 untrained man who has not learned to read these records, 

 species and types in life are enduring. From this illusion arose 

 the theory of special creation and permanence of type, a theory 

 which could not persist when the facts of change and the forces 

 causing it came to be studied in detail. 



But when men came to investigate the facts of individual 

 variation and to think of their significance, the current of life 

 no longer seemed at rest. Like the flow of a mighty river, ever 

 sweeping steadily on, never returning, is the movement of all 

 life. The changes in human history are only typical of the 

 changes that take place in all living creatures. In fact, human 

 history is only a part of one great life current, the movement of 

 which is everywhere governed by the same laws, depends on the 

 same forces, and brings about like results. 



Organic evolution, or bionomics, is one of the most com- 

 prehensive of all the sciences, including in its subject matter 

 not only all natural history, not only processes like cell division 

 and nutrition, not only the laws of heredity, variation, segre- 

 gation, natural selection, and mutual help, but all matters of 

 human history, and the most complicated relations of civics, 

 economics, and ethics. In this enormous science no fact can 

 be without a meaning, and no fact or its underlying forces can 

 be separated from the great forces whose interaction from 

 moment to moment writes the great story of life. 



And as the basis to the science of bionomics, as to all other 

 science, must be taken the conception that nothing is due to 



