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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 greatness, 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 sich selbst erschuf
Von Ewigkeit in schaffendem Beruf,
* * * der den Glauben schafft
Vertrauen, Liebe, Thätigkeit und Kraft."