It is probable that similar results will be obtained by all who will take the trouble to record the whole number of cases, instead of simply the number of deaths. The statistics of mortality in relation to this disease are deceptive, not only in regard to relative susceptibility of the human system to attacks at the different periods of life, but also in regard to the ratio of mortality of the disease itself. It is generally conceded that the chief mortality from this disease occurs during infancy or early childhood and in old age, cases rarely terminating fatally in youth or the more active period of adult life. Careful examination of cases will show that this fatality at the extremes of life is owing mainly to the greater tendency of the inflammation at those periods to extend directly from the bronchioles into the lobules of the lungs, thereby complicating the bronchitis with lobular pneumonia; and in more than half the cases reported under the head of bronchitis the fatal result was caused by the pneumonia instead of the bronchitis. [Footnote 1: See _Reynolds's System of Medicine_, Amer. ed., vol. ii. p. 318.] [Footnote 2: See _A Practical Treatise on the Diseases of Children_, by J. F. Meigs, M.D., and William Pepper, M.D., 4th ed., p. 189.] Neither recorded facts nor my own clinical observations show any decided difference in the susceptibility of the sexes to attacks of bronchial inflammation. Those occupations which confine the parties pursuing them much indoors, and at a temperature either too warm or too cold, strongly predispose to attacks of inflammation of the membrane lining the respiratory passages. Habitual exposure to a warm, confined air invites free exhalation from both the bronchial and cutaneous surfaces, with increased susceptibility, and {166} consequently renders the individual more susceptible to all external impressions. Habitual passive exposure indoors to a low temperature represses the exhalations and causes the retention of some of the products of tissue-change which by their presence in the blood render the individual more liable to attacks of inflammation on the supervention of any exciting cause. For the same reasons the habitual wearing of too much warm clothing on the one hand, or too little on the other, predisposes to attacks of bronchial disease. Another error of importance is the unequal adjustment of clothing to different parts of the cutaneous surface. In children especially we often see an abundance of warm clothing over the whole body, while the legs and feet and neck have but a single covering, and sometimes none. And even adult women often go out loaded with warm clothing, while their feet and ankles are protected only by thin shoes and stockings. All those occupations that surround the workmen with an atmosphere filled with irritating gases, floating particles of stone, metal, or charcoal, or with the dust from grain and many vegetable