"I have just finished my 'Origin,' and am now going to be a hermit for the rest of my life."

"The astonishment which I felt on first seeing a party of Fuegians on a wild and broken shore will never be forgotten by me, for the reflection at once rushed into my mind—such were our ancestors."

"I have tried lately to read Shakespeare, and found it so intolerably dull that it nauseated me."

"A dog might as well speculate on the mind of Newton."

"A scientific man ought to have no wishes, no affections – a mere heart of stone."