Charles Darwin — "Man tends to increase at a greater rate than his means of subsistence."

"The very essence of instinct is that it's followed independently of reason."

"Blushing is the most peculiar and most human of all expressions."

"We are not to be discouraged by the smallness of the means, but to remember that the greatest results are often produced by the accumulation of small effects."

"If a man were to read a book on the cultivation of fruit trees, and then attempt to practice it without having seen a single tree, he would not be more unsuccessful than those who attempt to philosoph…"

"Thus, from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows."