~Thinness in Children.~--Parents are to blame for much of the thinness seen in children, especially the nervous high-strung children whose energies outweigh their desire for food or, as is more often the case, their willingness to eat the proper foods. It is a mistaken kindness to cater to the whims and fancies of a child's appetite, and much harm is wrought by allowing the "trash" to overbalance the necessary building or repair food in the dietary. Not that sugar is not necessary, for it is particularly so at the age when the metabolic processes are faster than later in life, but it must be remembered that the body is being built up both in height and breadth. ~The Need for Building Foods.~--The skeleton and the muscular tissues cannot be constructed from sugar, hence the diet which consists chiefly of this food constituent is unbalanced and will sooner or later bring about disturbances which are very apt to result in emaciation. ~The causes of emaciation~ may be summarized as follows: (1) Those cases which are due to pathological conditions such as tuberculosis, anemia, typhoid fever, etc.; (2) Those induced by errors in diet and bad habits such as insufficient or improper food, loss of sleep, over-exercise, lack of ventilation in the sleeping apartment, which destroys the appetite; (3) Malformation or deformities of mouth, throat, or stomach which make it impossible for the individual to partake of sufficient food to cover the needs of the body; (4) Heredity ("constitutional thinness"). ~Regulating the Diet.~--As has been stated in a former chapter, any persistent loss of weight or failure to gain on the part of an infant whose chief business in life should be to grow, should be given immediate and careful attention. As a rule the diet is to blame; it is either improperly balanced, insufficient in amount, or poorly prepared, any of which might readily cause a disturbance to the delicate apparatus of the child. ~Diet and Habits.~--In adults, the diet and habits of life are in many cases to blame for the excessive thinness seen in many individuals. If the trouble can be traced to some abnormal condition, it can only be removed by relieving or checking the disease which induced it. The older methods of treating typhoid fever, for example, did nothing to prevent the progressive emaciation which was the result not only of the accelerated metabolism from the fever but also from the invasion of the intestinal tract by the specific bacteria which brought about a like result. In tuberculosis a similar breaking down of the tissues occurs, as is likewise the case in anemia and other diseases in which the functions of the blood-making organs are interfered with. Any of the above diseases may cause emaciation, and the treatment in most of the cases resolves itself in removing the cause as far as possible and in adjusting the diet.