Sympathy for the lowest animals is one of the noblest virtues with which man is endowed..

I am quite conscious that my speculations run beyond the bounds of true science....It is a mere rag of an hypothesis with as many flaw[s] & holes as ….

What wretched doings come from the ardor of fame; the love of truth alone would never make one man attack another bitterly..

The young blush much more freely than the old but not during infancy, which is remarkable, as we know that infants at a very early age redden from pa….

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

People complain of the unequal distribution of wealth [but it is a far greater] injustice that any one man should have the power to write so many bri….

Believing as I do that man in the distant future will be a far more perfect creature than he now is, it is an intolerable thought that he and all oth….

Man is developed from an ovule, about 125th of an inch in diameter, which differs in no respect from the ovules of other animals..

The age-old and noble thought of 'I will lay down my life to save another,' is nothing more than cowardice..

To my deep mortification my father once said to me, "You care for nothing but shooting, dogs, and rat-catching, and you will be a disgrace to yoursel….

Only picture to yourself a nice soft wife on a sofa with good fire, & books & music..

The main conclusion here arrived at ... is that man is descended from some less highly organized form..

Ignorance more frequently begets confidence than does knowledge..

The moral faculties are generally and justly esteemed as of higher value than the intellectual powers..

It is well-known that those who have charge of young infants, that it is difficult to feel sure when certain movements about their mouths are really ….

[T]he young and the old of widely different races, both with man and animals, express the same state of mind by the same movements..

The number of humble-bees in any district depends in a great degree on the number of field-mice, which destroy their combs and nests; and Mr. H. Newm….

Blushing is the most peculiar and the most human of all expressions. Monkeys redden from passion, but it would require an overwhelming amount of evid….

The lower animals, like man, manifestly feel pleasure and pain, happiness and misery. Happiness is never better exhibited than by young animals, such….

...all nature is perverse & will not do as I wish it..

To conclude, therefore, let no man out of a weak conceit of sobriety, or an ill-applied moderation, think or maintain, that a man can search too far ….