Whether our efforts are, or not, favored by life, let us be able to say, when we come near to the great goal, I have done what I could.
Louis PasteurVirulence appears in a new light which cannot but be alarming to humanity; unless nature, in her evolution down the ages (an evolution which, as we now know, has been going on for millions, nay, hundreds of millions of years), has finally exhausted all the possibilities of producing virulent or contagious diseases - which does not seem very likely.
Louis Pasteur