977. Hearing may be impaired by obstruction of the Eustachian tube. The closure of this canal diminishes the vibratory character of the air within the tympanum, in the same manner as closing the opening in the side of a drum. For the same reason, enlarged tonsils, inflammation and ulceration of the fauces and nasal passages during and subsequent to an attack of scarlet fever, and the inflammation attending the "sore throat" in colds, are common causes of this obstruction. 978. The treatment of such cases of defective hearing, is to have the tonsils, if enlarged, removed by a surgeon; for the inflammation and thickening of the parts remedial means should be applied, directed by a skilful physician. The nostrums for the cure of deafness are generally of an oleaginous character, and may be beneficial in cases of defective hearing caused by an accumulation of wax upon the drum of the ear, but in this respect they are no better than the ordinary animal oils. -=-=-=-=-=-=-=-=-=-=-=-= What is the remedy where there is an accumulation of wax? 977. What is the effect on hearing if the Eustachian tube is obstructed? 978. What is the treatment when deafness is caused by inflammation or ulceration the fauces? What is said of the nostrums used for deafness? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XLVIII MEANS OF PRESERVING THE HEALTH.[23] [23] It is advised, that a thorough review of the hygiene of the preceding chapters be given from the suggestions contained in this. 979. Our bodies are constituted in harmony with certain laws, and every person should learn these, in order to regulate his actions and the performance of his duties, so that health may be unimpaired, and the power of enjoyment, activity, and usefulness continue while life lasts. 980. It is a law of the bones and the muscles, that they should either be used in some vocation, or called into action by some social play and active sport. 981. All admit that food is necessary to sustain life; and unless it be of a proper quality, taken in proper quantities, and at proper times, the functions of the digestive organs will be deranged, and disease produced. 982. Pure air is essential to the full enjoyment of health. The impure air of unventilated rooms may be breathed, and the effect be so gradual as not to arrest attention; yet it is a violation of the physical laws, and, sooner or later, we pay the penalty in disease and suffering. -=-=-=-=-=-=-=-=-=-=-=-= 979. Why is it incumbent on every person to learn the laws of health? 980. Give a law of the muscles. 981. In preserving the health, is it necessary to give attention to the food which is eaten? Why? 982. What beside food is essential to the full enjoyment of health? What is said of the impure air of unventilated rooms? 983. What should be observed in regard to sleep? -=-=-=-=-=-=-=-=-=-=-=-=