"Man is descended from a hairy, tailed quadruped, probably arboreal in its habits, and an inhabitant of the Old World."

"I have always felt a strong feeling of gratitude to those who have helped me in my work."

"It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change."

"One day, on looking at an orchid, I was struck with the idea that the structure of the flower was adapted to the visits of insects."

"If I had my life to live over again, I would have made a rule to read some poetry and listen to some music at least once every week."