TUBERCULOSIS. 451 



charged into its cavity. During the extrusion of the accumu- 

 lated secretion from the gland, this little drop of pus was the first 

 to escape ; it then became uniformly spread out round the edges 

 of the drop of mucus which followed it. The j)us-formation in 

 the efferent duct may continue for a time as a purulent catarrh, 

 but it must certainly pass, and that soon, into a pus-formation 

 with loss of substance — into ulceration. A circular, shallow, 

 funnel-shaped ulcer is formed, girdled by a narrow zone of a 

 bright-yellow colour, which marks it off sharply from the 

 hyperaemic mucous membrane round it. In the centre of this 

 defect, the dilated orifice of the duct, or the gland itself after 

 suppurative destruction of its elements, forms a rounded hollow 

 of proportionate size, which is, at the same time, the deepest part 

 of the floor of the ulcer ; thus we see that the catarrhal ulcera- 

 tion of the gland- ducts is really peculiar enough to warrant our 

 distinguishing it from allied conditions. It is only when the 

 ulcer proceeds to extend in depth and breadth that its primordial 

 characters become effaced. The coalescence of contiguous ulcers 

 produces e. g. racemose outlines, like those which are usually 

 held to be characteristic of the " tuberculous " ulcer ; indeed 

 the racemose form is even more distinctly marked in these cases 

 than in tuberculous lesions of the bowels. The extension of the 

 ulcer in depth is favoured by the suppurative destruction of the 

 body of the mucous gland. A suppurative inflammation of its 

 capsular and interstitial connective tissue, leads to the disinte- 

 gration and solution of the acini ; the entire gland melts away ; 

 and when we reflect that the mucous glands of the air-passages 

 are situated, not in the mucous, but in the submucous layer, we 

 can readily perceive that these ulcers must be especially prone 

 to produce " excavations." As a fact, we soon find the floor of 

 the ulcer close to the tracheal rings, or the laryngeal cartilages ; 

 and this paves the way for a fresh series of lesions. 



The cartilages of the larynx and trachea, owing to their non- 

 vascular texture, and their obviously sluggish nutrition, are more 

 disposed te undergo necrosis en masse than a gradual destruction 

 by successive layers. When the inflammatory irritation reaches 

 the perichondrium, it not unfrequently happens that before the 

 cartilage itself has time to undergo any marked alteration in its 

 form, colour and consistency, the entire mass is isolated by a 

 suppurative perichondritis; it becomes a sequestrum, and is 



