WHY WE EAT SO MUCH 69 



number of heat units, providing all of the pound of food is 

 digested. 



Our bodies. Somewhat as a house is composed of a group 

 of bricks, or a sand heap of grains of sand, the human body is 

 composed of small divisions called cells. Ordinarily we cannot 

 see these cells because of their minuteness, but if we examine 

 a piece of skin, or a hair of the head, or a tiny sliver of bone 

 under the microscope, we see that each of these is composed 

 of a group of different cells. A merchant, watchful about the 

 fineness of the wool which he is purchasing, counts with his 

 lens the number of threads to the inch ; a physician, when he 

 wishes, can, with the aid of the microscope, examine the cells 

 in a muscle, or in a piece of fat, or in a nerve fiber. Not only 

 is the human body composed of cells, but so also are the bodies 

 of all animals, from the tiny gnat which annoys us, and the fly 

 which buzzes around us, to the mammoth creatures of the 

 tropics. The different cells do the work of the body ; the bone 

 cells build up the skeleton, the nail cells form the finger and 

 toe nails, the lung cells take care of breathing, the muscle cells 

 produce motion, and the brain cells are responsible for thought. 



Why we eat so much. The cells of the body are constantly, 

 day by day, minute by minute, breaking down and needing 

 repair, are constantly requiring replacement by new cells, 

 and, in the child, are continually increasing in number. The 

 repair of an ordinary machine, an engine, for example, is 

 made at the expense of money, but the repair and replacement 

 of our human cell machinery are accomplished at the expense 

 of food. More than one third of all the food we eat goes to 

 maintain the body cells, and to keep them in good order. It 

 is for this reason that we consume a large quantity of food. 

 If all the food we eat were utilized for energy, the housewife 

 could cook less, and the housefather could save money on 

 grocers' and butchers' bills. If you burn a ton of coal in an 



