Excerpt from A Manual of Pathological Anatomy, Vol. 4 of 4 We shall consider the abnormal conditions of the respiratory organs under three heads: - 1st. As they occur in the air-passages; namely, the larynx, trachea, and bronchi. 2d. As they occur in the pleurae; and - 3d. As they occur in the lungs. The deviations from the normal state occurring in the thyroid and thymus glands will be noticed in a Supplement. I. - Abnormal Conditions of the Air-Passages. 1. Deficiency and Excess of Formation. An entire deficiency of the air-passages invariably occurs in cases in which the lungs are absent. A partial deficiency, as for instance of the trachea, may occur without the lungs being necessarily absent, the bronchi in such cases being given off directly from the larynx. Under this head we must notice imperfect development of the air-passages, dependent on the deficiency of certain parts entering into their structure, as of some of the laryngeal cartilages or tracheal rings; and their malformations arising from the arrest of development both in length and width. An excess of formation is seen in the duplication occurring in double monsters, in which either the upper or the lower portion of the pulmonary apparatus is doubled; and here we must also place the occurrence of a supernumerary third bronchus, occasionally noticed on the right side in persons otherwise normally developed. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works."