All true histories contain instruction; though in some, the treasure may be hard to find, and when found, so trivial in quantity that the dry, shrivelled kernel scarcely compensates for the trouble of cracking the nut.

-Bronte«  , Anne
  Agnes Grey, ch.1.

What is commonly called love, namely the desire of satisfying a voracious appetite with a certain quantity of delicate white human flesh.

-Fielding, Henry
  Tom Jones, bk.6, ch.1.

When we run over libraries, persuaded of these principles, what havoc must we make? If we take in our hand any volume; of divinity or school metaphysics, for instance; let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matter of fact or existence? No.Commit itthen tothe flames: for it can contain nothing but sophistry and illusion.

-Hume, David
  An Enquiry Concerning Human Understanding, section12, pt.3.

I must have a prodigious quantity of mind; it takes me as much as a week to make it up.

-Twain, Mark pseudonym of  Samuel Langhorne Clemens
  The Innocents Abroad, ch.7.