Free Catching Fire: How Cooking Made Us Human by Richard Wrangham

was nearby and arrived within twenty-five minutes to find a bloody scene that he described eleven years later: “A large portion of the side was blown off, the ribs fractured, and openings made into the cavities of the chest and abdomen, through which protruded portions of the lung and stomach, much lacerated and burnt, exhibiting altogether an appalling and hopeless case. The diaphragm was lacerated and perforation made directly into the cavity of the stomach, through which food was escaping at the time your memorialist was called to his relief.”

    Beaumont took St. Martin to his own home. To everyone’s surprise, St. Martin survived, and Beaumont continued to house and care for him after he stabilized. In a few months the patient resumed a vigorous life, and he became so strong that he eventually even paddled his family in an open canoe from Mississippi to Montreal. Although the fist-sized wound mostly filled in, it never completely closed. For the rest of St. Martin’s life, the inner workings of his stomach were visible from the outside.

    The ambitious Beaumont realized that he had an extraordinary study opportunity. He began on August 1, 1825. “At 12 o’clock, M., I introduced through the perforation, into the stomach, the following articles of diet, suspended by a silk string, and fastened at proper distances, so as to pass in without pain—viz.:—a piece of highly seasoned a la mode beef; a piece of raw, salted, fat pork ; a piece of raw, salted, lean beef ; a piece of boiled, salted beef ; a piece of stale bread ; and a bunch of raw, sliced cabbage ; each piece weighing about two drachms; the lad [St. Martin] continuing his usual employment around the house.”

    Beaumont observed the stomach closely. He noted how quiet it was when it had no food, the rugae (muscle folds) nestled upon each other. When soup was swallowed, the stomach was at first slow to respond. “The rugae gently close upon it, and gradually diffuse it through the gastric cavity.” When Beaumont placed food directly on the stomach wall, the stomach became excited and its color brightened. There was a “gradual appearance of innumerable, very fine, lucid specks, rising through the transparent mucous coat, and seeming to burst, and discharge themselves upon the very points of the papillae, diffusing a limpid, thin fluid over the whole interior gastric surface.” For the first time, it was possible to watch digestion in action.

    Beaumont continued his experiments intermittently for eight years. He recorded in detail how long it took foods to be digested by the stomach and emptied into the duodenum. From those observations he drew two conclusions relevant to the effects of cooking.

    The more tender the food, the more rapidly and completely it was digested. He noted the same effect for food that was finely divided. “Vegetable, like animal substances, are more capable of digestion in proportion to the minuteness of their division . . . provided they are of a soft solid.” Potatoes boiled to reduce them to a dry powder tasted poor, but they were more easily digested. If not powdered, entire pieces remained long undissolved in the stomach and yielded slowly to the action of the gastric juice. “The difference is quite obvious on submitting parcels of this vegetation, in different states of preparation, to the operation of the gastric juice, either in the stomach or out of it.”

    The same principles held, said Beaumont, with respect to meat. “Fibrine and gelatine [muscle fibers and collagen in meat] are affected in the same way. If tender and finely divided, they are disposed of readily; if in large and solid masses, digestion is proportionally retarded. . . . Minuteness of division and tenderness of fibre are the two grand essentials for speedy and easy digestion.”

    In addition to “minuteness of division and tenderness,” cooking helped. He was explicit in the case of potatoes. “Pieces of raw potato, when submitted to the