INFLAMMATION OF ARTERIES AND VEINS. 255 



previous state by treatment with dilute hydrocliloric acid ; its^ 

 cells however have ceased to exist ; I have never seen anything 

 worthy of being called a bone-corpuscle. 



§ 220. So much for chronic endoarteritis in the narrower 

 sense of the term. An adequate estimate of the extensive lesions 

 which it causes, especially in the aorta — lesions which, in ad- 

 vanced cases, may leave hardly a square inch of its surface intact 

 — can only be formed from personal observation. To render 

 our anatomical sketch of the disease complete, we ought to say 

 something about two other processes, which the practitioner is 

 not at the pains to distinguish very strictly from chronic endo- 

 arteritis, inasmuch as they are in fact very commonly combined 

 with it. 



First then, a fatty degeneration of the intima may exist, with- 

 out any previous inflammatory overgrowth of the membranes — 

 a morbid change which is simply degenerative from the first, 

 and of whose immediate causes we know nothing. Histologi- 

 cally, the process is exactly like atheromatous degeneration ; a 

 fatty transformation of the cells (fig. 81) being followed by a 

 gradual liquefaction of the lamella3. This ^' fatty erosion" 

 (fettige Usur) of VircJioiL', starts immediately from the inner 

 surface of the vessel, and progresses from within outwards, 

 destroying the intima layer by layer. Moreover, the disease is- 

 always confined to small, sharply circumscribed spots ; in the 

 aorta and larger arteries it causes a very pretty marbhng of the 

 surface, the affected parts being rough, opaque and velvety. 



" Fatty erosion '' is often met with in persons otherwise quite 

 healthy. It must, however, tend directly to impair the resisting 

 power of the vessels. Experience tells us that when once the 

 intima is wholly destroyed, be the perforation ever so small, the 

 muscular media, notwithstanding its thickness, is miable to cope 

 with the pressure of the blood. The muscular fibres are sepa- 

 rated from one another, and a transverse fissure results, through 

 which the blood forces its way, either producing a dissecting 

 anemism by peeling off the adventitia, or else bm'sting through 

 it and escaping externally. This explains the frequency of 

 hemorrhages into the most diverse organs, occurring in con- 

 nexion with atheroma (e.g. the brain, kidneys, (fcc). Moreover, 

 fatty erosion of the inner coat has a certain share in causing the 

 transverse rupture of the aorta which leads to dissecting aneu- 



