The Great Experimental Principle, Then, Is Doubt,

[those] Who Have An Excessive Faith In Their Theories Or In Their Ideas Are Not Only Poorly Disposed To Make Discoveries, But They Also Make Very Poor Observations.

Ardent Desire For Knowledge, In Fact, Is The One Motive Attracting And Supporting Investigators In Their Efforts; And Just This Knowledge, Really Grasped And Yet Always Flying Before Them, Becomes At Once Their Sole Torment And Their Sole Happiness. Those Who Do Not Know The Torment Of The Unknown Cannot Have The Joy Of Discovery Which Is Certainly The Liveliest That The Mind Of Man Can Ever Feel.

Well-observed Facts, Though Brought To Light By Passing Theories, Will Never Die; They Are The Material On Which Alone The House Of Science Will At Last Be Built.

Put Off Your Imagination, As You Put Off Your Overcoat, When You Enter The Laboratory. Put It On Again, As You Put On Your Overcoat, When You Leave.

The Better Educated We Are And The More Acquired Information We Have, The Better Prepared Shall We Find Our Minds For Making Great And Fruitful Discoveries.