Every chemical substance, whether natural or artificial, falls into one of two major categories, according to the spatial characteristic of its form. The distinction is between those substances that have a plane of symmetry and those that do not. The former belong to the mineral, the latter to the living world.

Bernard was right. The germ is nothing, the terrain is everything.

The greatest disorder of the mind is to let will direct it.

How do you know that the incessant progress of science will not compel scientists to consider that life has existed during eternity, and not matter?

Chance favors the prepared mind.

You bring me the deepest joy that can be felt by a man whose invincible belief is that Science and Peace will triumph over Ignorance and War, that nations will unite, not to destroy, but to build, and that the future will belong to those who will have done most for suffering humanity.

Change only favours minds that are diligently looking and preparing for discovery.