444 RELATION OF PLANT PHYSIOLOGY TO OTHER SCIENCES. 



only out of the organized. So that growth of organisms appears to us 

 only a multiplication of what is already at hand. 



The progress of research has reduced to naught all the facts that 

 pointed toward spontaneous generation, and so we find ourselves duly 

 forced to turn away from spontaneous generation and to regard the 

 living substance as given, just as the physicist regards matter, and 

 takes no further thought as to the question of its origin. The most 

 exact research, even in the domain of matter, has led to impassable 

 boundaries, and the old riddles of the world and all its beings remain 

 unsolved in spite of all progress, and we know, perhaps more clearly 

 than the thinkers of earlier science epochs, that their solution lies beyond 

 the power of the human mind. They remain as unsolvable to the 

 greatest philosopher as well as to the simplest understanding. Other 

 faculties of the mind than those busied in the sober pursuit of science 

 may undertake to show a tangible relation between eternity and our 

 own insignificance. 



The mind of the most learned, free from the shadow of its own great- 

 ness, bows with the spirit of a child before the unknowable, before that 

 source of all Being which the greatest German poet has thus designated : 



" * * * der sicli selbst erschuf 

 Von Ewigkeit in schaffendeni Beruf, 

 * * * der den Glauben schafft 

 Vertrauen, Liebe, Thiitigkeit und Kraft." 



