In cases which do not thus tend to an early fatal result from the direct obstruction of the bronchi the respirations continue frequent, in young children sometimes reaching 50 or 60 respirations per minute, with much dyspnoea and restlessness; the pulse is quick, but not in proportion to the respirations; the expression of countenance is anxious and often slightly bloated, with a leaden hue of the prolabia; the wings of the nose expand and the chest heaves with each inspiration, giving a great variety of dry, whistling sounds generally throughout the whole chest, which after the first two or three days become mixed with sharply-defined submucous râles, and in the later stages give place to the latter entirely. The cough is frequent and inefficient, on account of the difficulty of getting sufficient air to make it satisfactory. The temperature varies from 38° to 39.5° C. (101-103° F.), seldom rising above the latter figure unless complicated with lobular pneumonia. The urine is generally scanty and deficient in the chlorine salts, and the bowels are inactive. The labored efforts of breathing in many cases make the upper and anterior part of the chest appear more prominent than natural, and even more resonant on percussion on account of temporary emphysema from over-distension of the air-cells in those parts, while in some parts of the lower and posterior portions there is less expansion and less resonance than natural from the occlusion of some of the bronchi and the partial obstruction of others leading to those parts of the lungs. Between the third and fifth days usually the mucous exudation, which up to that time had been scanty and tenacious, becomes more abundant and more opaque, and in two or three days more assumes a distinct muco-purulent character and is much more easily expectorated. As that which comes from the smaller bronchial tubes is less mixed with air, and consequently less frothy than that which comes from the larger tubes, the two qualities of matter may often be recognized in the same mouthful of sputa; and if the whole be placed in water, that from the smaller tubes will drop lower in the water, or sink to the bottom if detached from the other, which floats freely upon the surface. In acute cases, at the same time that the expectoration becomes more opaque and more easily dislodged by coughing, all the more important {172} symptoms begin slightly to improve, and by the end of the second week convalescence is fairly established. Many cases, however, are less acute, slower in progress, and do not reach convalescence in less than two or four weeks; and many of this class manifest a strong tendency to continue indefinitely in a chronic form, more especially in persons past the middle period of life. In some of the cases that do not continue in a chronic form, the bronchial membrane is left in a condition of such susceptibility that the attack is renewed on the slightest exposure to the exciting causes.