National Geographic : 1975 Mar
physiological rhythms on nutrient utilization. One grave misfortune: My record player no longer functions. I had counted heavily upon music to sustain me through the lonely months ahead. Now I have only books. And these, attacked by mildew, become exceed ingly disagreeable to handle. In fact, mildew spreads everywhere, even to the dials of my scientific equipment. Only the blue nylon of my tent remains immune. Early in my stay I heard the furtive noises of mice in the darkness. To eradicate this po tential source of disease, I set traps. The first "night" I netted a large male and a large fe male. To date, I have caught four more pairs. Curiously enough, each pair is smaller than the last. A feeding order of some kind? I be lieve that I have wiped out the whole mouse colony in the cave. I have not heard their tiny stirrings for many cycles. My evenings bring a particularly tedious routine. I must shave and meticulously pre serve the whiskers. Then, after carefully cleaning the skin surface, I must apply minia ture Beckman electrodes to my head and face; these will record the patterns of deep sleep, light sleep, and dream time. While investigation of sleep is a relatively young science, much has already been learned. Electroencephalograms show that sleep has several stages. It begins with a light initial LIVING QUARTERS FOR SURFACE CREW n d SURFACE LABORATORY \r , slumber called Stage I, and gradually deepens through Stages II and III, lasting roughly 40 minutes, into the profound oblivion of Stage IV. Then, again after a passage through intermediate phases, one begins the stage called REM, for the rapid eye movements that indicate dreaming. The cycle repeats four or five times in a typical night, but in general the deep slow-wave sleep occurs early and the ratio of REM sleep increases toward morning. Experiments indicate that the restorative power of sleep stems mainly from Stage IV; although the function of the REM phase is not clearly understood, investigators have found that some subjects, when deprived of it, dis play irritability and anxiety. 77TH DAY (APRIL 30, CYCLE 63) I have passed a significant mark. In 1962 I spent exactly 63 days in Scarasson, emerging in acute physical and emotional distress. Now, in my 63d cycle in Midnight Cave (I don't realize at the time that my "real" 63d day fell two weeks earlier), I am in excellent form. I notice, though, a fragility of memory. I recall nothing from yesterday. Even events of this morning are lost. If I do not write things down immediately, I forget them. I also begin to resent the telephone. Far from being a comfort, its presence serves as a malign reminder that I am alone, a captive. Midnight Cave, near Del Rio, Texas, provided n environment free from cold and bats, but ot from loneliness and mice. Communication vires link the author to assistants at the surface. lead shaved for electrodes, he shares a tender moment with his wife, Nathalie (left), the day before escending 100 feet into the cave for his ordeal.