“In nature nothing exists alone.”

“But man is a part of nature, and his war against nature is inevitably a war against himself.”

“Those who dwell, as scientists or laymen, among the beauties and mysteries of the earth, are never alone or weary of life.”

“The human race is challenged more than ever before to demonstrate our mastery, not over nature but of ourselves.”

“Only within the moment of time represented by the present century has one species -- man -- acquired significant power to alter the nature of the world. ”

“It is a curious situation that the sea, from which life first arose should now be threatened by the activities of one form of that life. But the sea, though changed in a sinister way, will continue to exist; the threat is rather to life itself.”

“Those who contemplate the beauty of the earth find reserves of strength that will endure as long as life lasts. There is something infinitely healing in the repeated refrains of nature -- the assurance that dawn comes after night, and spring after winter.”