62 PHYSIOLOGY AND HEALTH. 



and exhausted particles, having lost their living principle, are 

 then removed from their places in the tissues of the body, 

 and thrown into the veins, and thence carried away. Their 

 places must be supplied by new particles from the blood, 

 and the blood receives these from the digested food. The 

 body of the laborer, therefore, undergoes more rapid waste, 

 and needs a greater and more frequent supply of food, than 

 that of the people of sedentary habits, or idlers. It is a great 

 mistake, then, to suppose that all men, in whatever occupa- 

 tion engaged, should eat the same quantity of food. The 

 British government give to the troops, on their voyage to the 

 East Indies, on account of the quietness of their life, 30 per 

 cent, less of solid food than to the sailors, who are in con- 

 stant action on board the same ships. 



128. For this reason, the same man should not cat the 

 same quantity in all varieties of exercise. At one period, 

 he may be very laborious : he then wants more food than at 

 another time, when he may be engaged in lighter employ- 

 ment. This principle ought not to be forgotten by those 

 who make permanent changes in their occupations. Change 

 of habits presupposes change of nutritive wants. If the 

 action of the body be reduced, there is a reduction of waste, 

 and of nutritive want and digestive power. But, unfor- 

 tunately, the appetite is not readily reduced, nor is it per- 

 fectly easy to control it at once. But this is necessary, in 

 order to prevent indigestion. 



129. x Some young men, who have been accustomed to active 

 exercise, or even hard labor, suddenly change their occupa- 

 tions. They leave their farms or their workshops, and go to 

 school or to college, or to the lighter employment of cities. 

 Their habits of eating have been very properly adapted to 

 their habits of labor. While they were hard workers, they 

 were hearty eaters. Too frequently, their full diet is retained 

 after their hard labor of body is discontinued, and they still 

 eat the same amount of food as before. This is more than 

 the system now requires, and more than the stomach can 

 digest. That quantity, which was no more than sufficient to 



