INFLAMMATION OF THE COATS OF THE AORTA. 415 



In the second form, that of semi-cartilaginous induration, we find 

 opaque, bluish-white plates, like boiled white of egg, lying upon the 

 inner surface of the artery. Here, too, the tissue of the tunica intima 

 is softened and infiltrated, but it remains firmer and more consistent 

 than in the other form, and it afterward assumes a cartilaginous hard- 

 ness. Under the microscope, numerous fusiform and reticulate cells 

 can be seen in the semi-cartilaginous variety, but, above all, broad 

 fasciculi of connective tissue are visible, which plainly form an imme- 

 diate continuation of the lamellar fibres of the tunica intima. 1 



The further changes which these inflammatory products undergo 

 are : 1. Fatty metamorphosis ; 2. Calcification or ossification. 



In the gelatinous thickening, fatty metamorphosis begins chiefly in 

 the superficial portion, commencing in these cells, while the interme- 

 diate substance breaks down, and the surface becomes rough and 

 tufted. This process is called " fettige Usur " " fatty consumption." 



In semi-cartilaginous thickening, fatty metamorphosis begins in the 

 deeper layers. At first, numerous drops of fat are deposited around 

 the nuclei of the connective-tissue cells, which become transformed into 

 star-shaped cells of fatty granules. These ultimately perish, and the 

 fat-molecules are liberated. The bundles of connective tissue also break 

 down, and thus, deep in the interior, a pea-soup colored, fatty paste is 

 formed, consisting of fat-molecules, numerous crystals of cholesterin, and 

 debris of connective tissue, constituting true atheroma. As long as the 

 greasy paste remains separated from the current of the blood by a thin 

 film of the internal coat, it is called an atheromatous pustule.* After- 

 ward, when the covering has broken down, after its contents have been 

 washed away, and an irregular loss of substance, with ragged edges, 

 has formed, we speak of an atheromatous ulceration. Atheroma and 

 " usur " bear the same relation to one another as abscess and ulcer. 



Calcification depends upon a deposit of salts of lime in the deeper 

 layers of the semi-cartilaginous thickening. In the plates of lime thus 

 formed we sometimes find bodies analogous to bone-corpuscles, jagged 

 in form, and furnished with prolongations, which are the residua of 

 connective tissue-cells, so that we then are warranted in employing the 

 term ossification. While the smaller arteries may become converted 

 into tubes, with rigid walls, from deposit of earthy matter, ossification 

 of the aorta usually appears in the shape of separate plates and scales, 

 of variable size, which form shallow depressions upon the inner surface 

 of the vessel, and which are separated from the blood by the interven- 

 tion of a thin film of the tunica intima. By-and-by the ossification 

 reaches the surface itself; the scales of bone are completely exposed, 

 * The term " pustule " is not used here in its proper sense, and is solely applicable 

 to the macroscopic appearance of these little inflammatory foci. 



