It is a very mysterious Law which guards in this way the portals of the living world.

And if there is one thing in Nature more worth pondering for its strangeness it is the spectacle of this vast helpless world of the dead cut off from the living by the law of Biogenesis and denied forever the possibility of resurrection within itself.

So very strange a thing, indeed, is this broad line in Nature, that Science has long sought to obliterate it.
Biogenesis stands in the way of some forms of Evolution with such stern persistency that the assaults upon this law for number and thoroughness have been unparalleled.

But, as we have seen, it has stood the test.
Nature, to the modern eye, stands broken in two.

The physical laws may explain the inorganic world; the biological laws may account for inorganic.