THE BREATH OF LIFE 



now; it was not here yesterday, and it may not be 

 here to-morrow; it comes and goes. Life is like a 

 bird of passage which alights and tarries for a time 

 and is gone, and the places where it perched and 

 nested and led forth its brood know it no more. Ap- 

 parently it flits from world to world as the great 

 cosmic spring comes to each, and departs as the 

 cosmic winter returns to each. It is a visitor, a 

 migrant, a frail, timid thing, which waits upon the 

 seasons and flees from the coming tempests and 

 vicissitudes. 



How casual, uncertain, and inconsequential the 

 vital order seems in our own solar system a mere 

 incident or by-product in its cosmic evolution! As- 

 tronomy sounds the depths of space, and sees only 

 mechanical and chemical forces at work there. It 

 is almost certain that only a small fraction of the 

 planetary surfaces is the abode of life. On the earth 

 alone, of all the great family of planets and satellites, 

 is the vital order in full career. It may yet linger 

 upon Mars, but it is evidently waning. On the in- 

 ferior planets it probably had its day long ago, while 

 it must be millions of years before it comes to the 

 superior planets, if it ever comes to them. What a 

 vast, inconceivable outlay of time and energy for 

 such small returns! Evidently the vital order is 

 only an episode, a transient or secondary phase of 

 matter in the process of sidereal evolution. Astro- 

 nomic space is strewn with dead worlds, as a New 

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