In the arts of life main invents nothing; but in the arts of death he outdoes Nature herself, and produces by chemistry and machinery all the slaughter of plague, pestilence and famine. ... There is nothing in Man's industrial machinery but his greed and sloth: his heart is in his weapons.

Christianity might be a good thing if anyone ever tried it.

Now that we have learned to fly the air like birds, swim under water like fish, we lack one thing - to learn to live on earth as human beings.

We must not stay as we are, doing always what was done last time; or we shall stick in the mud.

Every doctor will allow a colleague to decimate a whole countryside sooner than violate the bond of professional etiquette by giving him away.

Nothing is ever done in this world until men are prepared to kill one another if it is not done.

German and Spanish are accessible to foreigners: English is not accessible even to Englishmen.