... probably all the organic beings which have ever lived on this earth have descended from some one primordial form, into which life was first breathed.

The more I study nature, the more I become impressed with ever-increasing force with the conclusion, that the contrivances and beautiful adaptations slowly acquired through each part occasionally varying in a slight degree but in many ways, with the preservation or natural selection of those variations which are beneficial to the organism under the complex and ever-varying conditions of life, transcend in an incomparable degree the contrivances and adaptations which the most fertile imagination of man could suggest with unlimited time at his disposal.

The loss of these tastes [for poetry and music] is a loss of happiness, and may possibly be injurious to the intellect, and more probably to the moral character, by enfeebling the emotional part of our nature.

It may be doubted that there are many other animals which have played so important a part in the history of the world as have these lowly organized creatures.

At no time am I a quick thinker or writer: whatever I have done in science has solely been by long pondering, patience and industry.

The traveler may feel assured, he will meet with no difficulties or dangers, excepting in rare cases, nearly so bad as he beforehand anticipates. In a moral point of view, the effect ought to be, to teach him good-humored patience, freedom from selfishness, the habit of acting for himself, and of making the best of every occurrence.

Ignorance more frequently begets confidence than does knowledge.