You ask about my opinion on vivisection. I quite agree that it is justifiable for real investigations on physiology; but not for mere damnable and detestable curiosity.

Jealousy was plainly exhibited when I fondled a large doll, and when I weighed his infant sister, he being then 15? months old. Seeing how strong a feeling of jealousy is in dogs, it would probably be exhibited by infants at any earlier age than just specified if they were tried in a fitting manner

I have been speculating last night what makes a man a discoverer of undiscovered things; and a most perplexing problem it is. Many men who are very clever - much cleverer than the discoverers - never originate anything.

At some future period, not very distant as measured by centuries, the civilised races of man will almost certainly exterminate and replace throughout the world the savage races. At the same time the anthropomorphous apes, as Professor Schaaffhausen has remarked, will no doubt be exterminated. The break will then be rendered wider, for it will intervene between man in a more civilised state as we may hope, than the Caucasian and some ape as low as a baboon, instead of as at present between the negro or Australian and the gorilla.

...I feel most deeply that the whole subject is too profound for the human intellect. A dog might as well speculate on the mind of Newton.— Let each man hope & believe what he can.—

We are optimists, until we are not.

If I had my life to live over again, I would have made a rule to read some poetry and listen to some music at least once every week.