History Shows That The Human Mind, Fed

It Is Always Advisable To Perceive Clearly Our Ignorance.

The Lower Animals, On The Other Hand, Must Have Their Bodily Structure Modified In Order To Survive Under Greatly Changed Conditions. They Must Be Rendered Stronger, Or Acquire More Effective Teeth Or Claws, In Order To Defend Themselves From New Enemies; Or They Must Be Reduced In Size So As To Escape Detection And Danger. When They Migrate Into A Colder Climate They Must Become Clothed With Thicker Fur, Or Have Their Constitutions Altered. If They Fail To Be Thus Modified, They Will Cease To Exist.

We Cannot Fathom The Marvelous Complexity Of An Organic Being; But On The Hypothesis Here Advanced This Complexity Is Much Increased. Each Living Creature Must Be Looked At As A Microcosm--a Little Universe, Formed Of A Host Of Self-propagating Organisms, Inconceivably Minute And As Numerous As The Stars In Heaven.

During My Second Year At Edinburgh [1826-27] I Attended Jameson's Lectures On Geology And Zoology, But They Were Incredible Dull. The Sole Effect They Produced On Me Was The Determination Never As Long As I Lived To Read A Book On Geology.

I Am A Firm Believer, That Without Speculation There Is No Good And Original Observation.