[Herschel and Humboldt] stirred up in me a burning zeal to add even the most humble contribution to the noble structure of Natural Science. No one or a dozen other books influenced me nearly so much as these two. I copied out from Humboldt long passages about Teneriffe and read them aloud on one of [my walking excursions].

Why does man regret, even though he may endeavour to banish any such regret, that he has followed the one natural impulse, rather than the other; and why does he further feel that he ought to regret his conduct? Man in this respect differs profoundly from the lower animals.

Worms have played a more important part in the history of the world than humans would at first suppose.

...he who remains passive when over-whelmed with grief loses his best chance of recovering his elasticity of mind.

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.'

I trust and believe that the time spent in this voyage ... will produce its full worth in Natural History; and it appears to me the doing what little we can to increase the general stock of knowledge is as respectable an object of life, as one can in any likelihood pursue.

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