Free Six Feet Over: Adventures in the Afterlife by Mary Roach Page A

experiment on five more patients. A paper summarizing his findings ran in the journal American Medicine in 1907. In the months that followed, dubious M.D s launched their criticisms in lengthy letters to the editor. Macdougall countered them all. One correspondent pointed out that the sphincter and pelvic floor muscles relax at death, and that the loss was perhaps urine and/or feces. Macdougall patiently replied that if this were the case, the weight would remain upon the bed and, therefore, upon the scale. Someone else suggested that the dying patients’ final exhalation might have contributed to the drop in weight. To prove that it hadn’t, Macdougall gamely climbed onto the cot and exhaled “as forcibly as possible,” while Sproull watched the scale. No change was observed.
    The most likely culprit was something called “insensible loss”: body weight that is continually being lost through evaporating perspiration and water vapor in one’s breath. Macdougall claimed to have accounted for this. His first patient, he wrote, lost water weight at the rate of an ounce per hour, far too slowly for insensible loss to explain the sudden three-quarter-ounce drop at death.
       
    THE HISTORICAL AUTHORITY on insensible weight loss is a Paduan physiologist named Sanctorius. Known humdrumly as the “founding father of metabolic balance studies,” Sanctorius coined the term “insensible perspiration” in 1690,in a diverting volume entitled Medicina statica . * To aid him in his research, Sanctorius devised an experimental scale of his own. He suspended a platform on a massive steelyard scale. The platform held a bench with a hole cut out of the center of it and a bucket underneath it, and in front of the platform stood a supper table: Out box and In box. Sanctorius sat himself down on the platform, enjoyed a meal, and then sat around on the scale for eight hours, availing himself of the bucket when needed. He then weighed, to use his exuberantly capitalized phrasings, “the Excrements of the Guts”—observing on an unrelated tangent that “the thick ones are lighter and swim .” Sanctorius found that a small portion of the food weight remained unaccounted for, i.e., wasn’t down there in the bucket. This he ascribed to evaporated sweat and breath vapor, which he collectively dubbed insensible perspiration.
    Sanctorius calculated that an eight-pound intake of meat and drink will, over one day, yield five pounds of insensible perspiration—or an average of three ounces of sweat and breath vapor lost per hour: three times the rate Macdougall observed. At one point Sanctorius describes the digestion of “a supper of eight pounds.” † It soon became clear there was little overlap between the dripping trencherman of Sanctorius’s day and Macdougall’s dry little consumptives. I skipped ahead to Section VI, which was all about the effects of immoderate coitus on insensible perspiration. Sanctorius effected thequaint habit of presenting his findings in the form of aphorisms. As in, “Aphorism XXXIX: Such a Motion of a Body as resembles that of a Dog in Coition, is more hurtful than a bare Emission of Semen; for the latter wearies only the internal Parts, but the other tires both the Bowels and the Nerves.” Or “Aphorism XL: To use Coition standing, after a Meal, is hurtful; because as it is upon a full Meal, it hinders the Offices of the Bowels.” Sanctorius preached that by obstructing insensible perspiration, immoderate sex led to everything from “Palpitations in the Eyebrows and Joynts” to a hardening of the tunicles of the eyes—and here we have what I surmise to be the original striking of the masturbation-makes-you-go-blind myth. Sanctorius preached a carnal moderation that seemed almost killjoy—all the more so for the book’s wanton promotion of oysters as sources “of the greatest possible nourishment.”
       
    TO GET TO THE bottom of the insensible weight loss conundrum—is it an ounce per