Agreeably to this definition, in his view of Phthisis Pulmonalis, Dr. Cullen makes ulceration of the lungs and hectic fever essential to its existence, and seems rather to consider the preceding symptoms a cause of this ulceration and fever, than as constituting an integrant part of the disease. Nor is the place assigned by him to Phthisis Pulmonalis, in his Nosological Arrangement, more correct than his definition of it. He places it in the order Hæmorrhagiæ, and considers it merely as a consequence of Hæmoptysis. Even if it were always excited by hæmorrhage from the lungs, it would be improperly thus placed; but as that, even by Dr. Cullen, is considered merely as one among many exciting causes, the arrangement is altogether inadmissible. But if it be admitted, according to the view which will be hereafter taken of Hæmoptysis in this treatise, that it is rather a symptom than a cause of Consumption, the propriety of another arrangement will be evident. Accordingly Phthisis Pulmonalis is placed by Dr. Hosack, as one of the Phlegmasiæ. This disposition appears to be the most proper that has hitherto been suggested, and as such I shall adopt it. But before we can ascertain the character and treatment of any diseases, it is necessary minutely to examine their causes and symptoms. Primary Phthisis Pulmonalis first claims our attention. Its predisposing causes may be mostly arranged into five classes, as they depend on organization, age, sex, occupation and climate. Organization predisposes to Consumption, by mal-conformation of the chest, which may be either natural or accidental; and an hereditary internal structure not depending on the external form of the thorax. For it is observed, that in some instances, those who have every part of the external configuration, such as is generally attributed to persons predisposed to Consumption, yet shall be free from this disease; while on the other hand, some whose chests are externally perfectly well formed, have been subject to catarrhal and inflammatory complaints of the lungs, terminating in Phthisis. The form of chest peculiar to many Phthisical patients, “is occasioned by the sternal or breast-bone being pressed too much in upon the substance of the lungs: thus the clavicles and shoulder-blades are thrust out of their proper position, and made to assume, in some measure, the form of wings, to which indeed they have been with propriety compared, just raised from the body and about to expand for flight. By this internal direction of the sternum, the full expansion and proper sweep of the ribs is likewise prevented, and an unnatural curvature or prominence is occasioned on either side of the breast, with a corresponding central depression.”[4] This is the peculiar form to which the term narrow chest is generally applied. A flattened or any other unnatural figure of the chest may produce the same injury.