Nutrition.—­ The nutrition of the body is dependent on the food supply, digestion and excretion.  The growing girl should eat more than the adult woman, because of her more active life and of the fact that the food which she takes must not only replace the worn-out material of the body, but also provide new material needed for growth.  Insufficient food and food of defective quality and composition work proportionately for more harm during the growing age.

The full adult weight is not attained before the twenty-fifth year.  When the final growth of the body and development of the vital organs is completed, the function of food is simply to replace waste with new material and to furnish material for the development of force.

Diet.—­ The diet should be a mixed one, consisting of the various kinds of fresh meats, fish, milk, eggs, poultry, vegetables, fruit, and fat in the shape of cream, butter, and the fat of beef and mutton.  Animal food improves the condition of the muscles, which are made firmer than they would be through a vegetable diet.  Meat in general has a more stimulating effect upon the system and is more strengthening than vegetable food, and it gives rise to a sensation of energy and activity.  The common estimate is that meat should occupy one-fourth and vegetable food three-fourths of a mixed diet.

Common salt in moderate quantity is essential, but all highly spiced or seasoned foods should be avoided, also pickles and vinegar.  All “sweets” are harmful, because they destroy the appetite for other things and upset the digestion.  Tea and coffee should be tabooed, as well as all alcoholic beverages.

Good digestion depends for the most part on serving the meals at the same hour every day, eating leisurely, and masticating the food well.  There is a great tendency on the part of the school girl to sleep late in the morning, then “bolt” her breakfast in order to get to school in time.  Nothing could be more pernicious to the digestion, unless it is the eternal nibbling of candy.

A healthy girl needs nothing between meals.  A delicate girl will be the better for a glass of milk in the middle of the morning and at bed-time; or pure beef juice may be given instead.

Water.—­ Water is needed to keep the kidneys properly flushed.  The amount of urine secreted during the twenty-four hours should be three pints.  Of course it will be less than this if the quantity of water is insufficient.  In addition to the urine about ten ounces of water are lost from the surface of the lungs, and eighteen ounces from the skin, making a total of about five pints; and this quantity of water must be taken daily in order to maintain the equilibrium of the body.  The solid food of a mixed diet contains from fifty to sixty per cent. of water, so that about twenty-five ounces of water are taken into the system daily as an integral part of the food.  In addition, three pints more should be taken as plain water.  The bladder acts as a reservoir for the urine, and should be emptied at least three or four times a day.