Thoreau writes in reply to H. G. O. Blake’s letter of 27 March 1848:
“We must have our bread.” But what is our bread? Is it baker’s bread? Methinks it should be very home-made bread. What is our meat? Is it butcher’s meat? What is that which we must have? Is that bread which we are now earning sweet? Is it not bread which has been suffered to sour, and then been sweetened with an alkali, which has undergone the vinous, acetous, and sometimes the putrid fermentation, and then been whitened with vitriol? Is this the bread which we must have? Man must earn his bread by the sweat of his brow, truly, but also by the sweat of his brain within his brow. The body can feed the body only. I have tasted but little bread in my life. It has been mere grub and provender for the most part. Of bread that nourished the brain and the heart, scarcely any. There is absolutely none even on the tables of the rich.