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

Herrmann Pidoux and Armand Trousseau stated 'Disease exists within us, because of us, and through us', Pasteur did not entirely disagree, 'This is true for certain diseases', he wrote cautiously, only to add immediately: 'I do not think that it is true for all of them'.

Without theory, practice is but routine born of habit. Theory alone can bring forth and develop the spirit of inventions.

As in the experimental sciences, truth cannot be distinguished from error as long as firm principles have not been established through the rigorous observation of facts.

Fortune favors the well-prepared.

Blessed is he who carries within himself a God, an ideal, and obeys it.

Nothing is lost and nothing is created in the operations of art as those of nature.