"Quietude and warmth contribute greatly to the fattening process. This is a fact which has not only been developed by science, but proved by actual practice. The manner in which these agents operate is simple, and easily explained. Motion increases respiration, and the excess of oxygen, thus taken, requires an increased quantity of carbon, which would otherwise be expended in producing fat. So, likewise, _cold robs the system of animal heat_; to supply which, more oxygen and more carbon must be employed in extra combustion, to restore the diminution of temperature. Nature enforces the restoration of warmth, by causing cold to produce both hunger and a disposition for motion, supplying carbon by the gratification of the former, and oxygen by the indulgence of the latter. The above facts are illustrated by Lord Ducie:-- "One hundred sheep were placed in a shed, and ate twenty pounds of Swedish turnips each per day; whilst another hundred, in the open air, ate twenty-five pounds each; and at that rate for a certain period: the former animals weighed each thirty pounds more than the latter; plainly showing that, to a certain extent, _warmth is a substitute for food_. This was also proved, by the same nobleman, in other experiments, which also illustrated the effect of exercise. "No. 1. Five sheep were fed in the open air, between the 21st of November and the 1st of December. They consumed ninety pounds of food per day, the temperature being 44°. At the end of this time, they weighed two pounds less than when first exposed. "No. 2. Five sheep were placed under shelter, and allowed to run at a temperature of 49°. They consumed at first eighty-two pounds, then seventy pounds, and increased in weight twenty-three pounds. "No. 3. Five sheep were placed in the same shed, but not allowed any exercise. They ate at first sixty-four pounds, then fifty-eight pounds, and increased in weight thirty pounds. "No. 4. Five sheep were kept in the dark, quiet and covered. They ate thirty-five pounds per day, and increased in weight eight pounds. "A similar experiment was tried by Mr. Childers, M. P. He states, that eighty Leicester sheep, in the open field, consumed fifty baskets of cut turnips per day, besides oil cake. On putting them in a shed, they were immediately able to consume only thirty baskets, and soon after but twenty-five, being only one half the quantity required before; and yet they fattened as rapidly as when eating the largest quantity.