Whatever your career may be, do not let yourselves become tainted by a deprecating and barren scepticism.

The flavor of wine is like delicate poetry.

Imagination should give wings to our thoughts but we always need decisive experimental proof, and when the moment comes to draw conclusions and to interpret the gathered observations, imagination must be checked and documented by the factual results of the experiment.

You have not succeeded in your experiments, that is all there is to it.

To know how to wonder and question is the first step of the mind toward discovery.

Never will the doctrine of spontaneous generation recover from the mortal blow struck by this simple experiment.

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.