The swells and waves of the ocean continue to roll in, calm and relentless. Bioluminescent organisms spark in the breakers. Plankton rise through the water to feed. Lobsters crawl out from the crevices of rocks to feed. Grunion move in to lay eggs and fertilize them. In the rocks along Mission Bay and the harbor, rats sinuate their way toward discarded food wrappers and restaurant kitchens.
Cloud masses form, the marine layer builds up, and what used to be known as el velo de la luz (the veil of light) moves inland, shrouds the sky. It's a box lid that shuts us in or a blanket that protects us from the limitless darkness.
Sleeping humans and some birds and reptiles enter REM sleep, D-sleep. In the area of the humans' brain stems called the raphé system, large neurons reduce their activity. Pulse rates, respiratory rates, blood pressures rise and fall, muscle tone lowers. Cerebral cortexes are activated, sensory images flood the sleeping mind. Neurons in the brain stem release norepinephrine, serotonin, acetylcholine into the forebrain. It is speculated that changes in the proportion of these chemicals, along with certain activity in the forebrain, produce nightmares. In former times these were attributed to intercourse with incubi.
The wakeful ear is pricked by snapping twigs, by the scrabblings of roof rats leaving attics and palm trees to sniff out snails, fruit rinds, rotting meat. Cars peel out angrily from alleys. Backfires or gunshots? Dark reddish-brown American cockroaches fly out from palm trees and sewer drains to crawl on the sidewalks downtown. Garbage-pickers discreetly heave squeaking dumpster lids up, foraging for breakfast, income, and outerwear. Refrigerators click on and hum. Creaks and yowls from neighbors' bedrooms reach guilty ears, muffled and enticing: people beg to be taken, call for God.
-- Mary Lang