In bronchitis, besides the ordinary symptoms of a severe cold in the head, as sneezing, running of mucus from the nose, sore throat and some hoarseness perhaps, and languor and soreness in the muscles, there is at first a feeling of tightness, pressure, and rawness in the region of the breastbone, with a harsh, dry cough. The coughing causes a strain of the diaphragm (the muscle which forms the floor of the chest), so that there are often pain and soreness along the lower borders of the chest where the diaphragm is attached to the inside of the ribs. After a few days the cough becomes looser, greatly to the patient's comfort, and a mixture of mucus and pus is expectorated. In a healthy adult such a cough is usually not in itself a serious affair, and apart from the discomfort of the first day or two, there is not sufficient disturbance of the general health to interfere with the ordinary pursuits. The temperature is the best guide in such cases; if it is above normal (98-3/5 deg. F.) the patient should stay indoors. In infants, young children, enfeebled or elderly people, bronchitis may be a serious matter, and may be followed by pneumonia by extension of the inflammation from the small bronchial tubes into the air sacs of the lungs, and infection with the pneumonia germ. The principal signs of severe attacks of bronchitis are rapid breathing, fever, and rapid pulse. The normal rate of breathing in adults is seventeen a minute, that is, seventeen inbreaths and seventeen outbreaths. In children of one to five years the normal rate is about twenty-six breathing movements a minute. In serious cases of bronchitis the rate may be twenty-five to forty in adults, or forty to sixty in children, per minute. Of course the only exact way of learning the nature of a chest trouble is thorough, careful examination by a physician, for cough, fever, rapid breathing and rapid pulse occur in many other diseases besides bronchitis, particularly pneumonia. Pneumonia begins suddenly, often with a severe chill, headache, and general pains like _grippe_. In a few hours cough begins, short and dry, with violent, stabbing pain in one side of the chest, generally near the nipple. The breathing is rapid, with expanding nostrils, the face is anxious and often flushed. The matter coughed up at first is often streaked with blood, and is thick and like jelly. The temperature is often 104 deg.-105 deg. F. If the disease proceeds favorably, at the end of five, seven, or ten days the temperature, breathing, and pulse become normal suddenly, and the patient rapidly emerges from a state of danger and distress to one of comfort and safety. The sudden onset of pneumonia with chill, agonizing pain in side, rapid breathing, and often delirium with later bloody or rusty-colored, gelatinous expectoration, will then usually serve to distinguish it from bronchitis, but not always.