Each organic being is striving to increase in a geometrical ratio . . . each at some period of its life, during some season of the year, during each generation or at intervals, has to struggle for life and to suffer great destruction . . . The vigorous, the healthy, and the happy survive and multiply.

Whenever I have found that I have blundered, or that my work has been imperfected, and when I have been contemptuously criticised, and even when I have been overpraised, so that I have felt mortified, it has been my greatest comfort to say hundreds of times to myself that 'I have worked as hard as I could, and no man can do more than this.'

It's an awful stretcher to believe that a peacock's tail was thus formed but ... most people just don't get it - I must be a very bad explainer

It is a fatal fault to reason whilst observing, though so necessary beforehand and so useful afterwards.

I long to set foot where no man has trod before.

Thus disbelief crept over me at a very slow rate, but at last was complete. The rate was so slow that I felt no distress, and have never since doubted even for a single second that my conclusion was correct.

Hence, a traveller should be a botanist, for in all views plants form the chief embellishment.