The Constancy Of The Internal Environment Is

We Must Alter Theory To Adapt It To Nature, But Not Nature To Adapt It To Theory.‎

Proof That A Given Condition Always Precedes Or Accompanies A Phenomenon Does Not Warrant Concluding With Certainty That A Given Condition Is The Immediate Cause Of That Phenomenon. It Must Still Be Established That When This Condition Is Removed, The Phenomen Will No Longer Appear.

The Great Experimental Principle, Then, Is Doubt, That Philosophic Doubt Which Leaves To The Mind Its Freedom And Initiative, And From Which The Virtues Most Valuable To Investigators In Physiology And Medicine Are Derived.

A Man Of Science Rises Ever, In Seeking Truth; And If He Never Finds It In Its Wholeness, He Discovers Nevertheless Very Significant Fragments; And These Fragments Of Universal Truth Are Precisely What Constitutes Science.

A Contemporary Poet Has Characterized This Sense Of The Personality Of Art And Of The Impersonality Of Science In These Words,-'art Is Myself; Science Is Ourselves. '