Even The Humblest Mammal's Strong Sexual, Parental,

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.

It May Be Doubted That There Are Many Other Animals Which Have Played So Important A Part In The History Of The World As Have These Lowly Organized Creatures.

It Strikes Me That All Our Knowledge About The Structure Of Our Earth Is Very Much Like What An Old Hen Would Know Of The Hundred-acre Field In A Corner Of Which She Is Scratching.

I Have Deeply Regretted That I Did Not Proceed Far Enough At Least To Understand Something Of The Great Leading Principles Of Mathematics, For Men Thus Endowed Seem To Have An Extra Sense.

One General Law, Leading To The Advancement Of All Organic Beings, Namely, Multiply, Vary, Let The Strongest Live And The Weakest Die.