If he can take a few minutes of concentrated rest at odd times, or even only one to three minutes at a time when he can get no more, he will benefit out of all proportion. The nerves will be soothed, the mind relaxed from its cares, the body-battery recharged, and the emotions calmed.

-- Notebooks Category 3: Relax and Retreat > Chapter 3: Relax Body, Breath, Mind > # 5