All relationships change the brain - but most important are the intimate bonds that foster or fail us, altering the delicate circuits that shape memories, emotions and that ultimate souvenir, the self.

A flower's fragrance declares to all the world that it is fertile, available, and desirable, its sex organs oozing with nectar. Its smell reminds us in vestigial ways of fertility, vigor, life-force, all the optimism, expectancy, and passionate bloom of youth. We inhale its ardent aroma and, no matter what our ages, we feel young and nubile in a world aflame with desire.

For better or worse, zoos are how most people come to know big or exotic animals. Few will ever see wild penguins sledding downhill to sea on their bellies, giant pandas holding bamboo lollipops in China or tree porcupines in the Canadian Rockies, balled up like giant pine cones.

Happiness doesn't require laughter, only well-being and a sense that the world is breaking someone else's heart, not mine.

Violets smell like burnt sugar cubes that have been dipped in lemon and velvet.

In Manhattan last month I heard a woman borrowing the jargon of junkies to say to another, 'Want to do some chocolate?'

No matter how politely one says it, we owe our existence to the farts of blue-green algae.