Let us read it again: "'Let us first place," he read from the book, 'vividly in our imagination the picture of the two great Kingdoms of Nature, the inorganic and the organic, as these now stand in the light of the Law of Biogenesis.

What essentially is involved in saying that there is no Spontaneous Generation of Life?
It is meant that the passage from the mineral world is hermetically sealed on the mineral side.

This inorganic world is staked off from the living world by barriers which have never yet been crossed from within.

No change of substance, no modification of environment, no chemistry, no electricity, nor any form of energy, nor any evolution can endow any single atom of the mineral world with the attribute of life.

Only by bending down into this dead world of some living form can these dead atoms be gifted with the properties of vitality, without this preliminary contact with life they remain fixed in the inorganic sphere forever.