396 LECTURE XVI. 



regarded the ossification of vessels as a change belonging 

 to the same category as atheroma. Haller and Crell be- 

 lieved that the ossification proceeded from the athero- 

 matous matter, and that this was a juice which, like that 

 exuding under the periosteum of bone, was capable of 

 generating plates of bone out of itself. Afterwards it 

 was recognized that atheromasia and ossification were two 

 parallel processes, which, however, might be referred to 

 a common origin. Now it would, I think, have been 

 logical, if in the next place an understanding had been 

 come to as to what this origin was, from which the athe- 

 romatous change and the ossification proceeded. But, 

 instead of this, the track of fatty degeneration was pur- 

 sued, and thus the atheromatous process was extended 

 to a number of vessels, in which, on account of the thin- 

 ness and the simple structure of their walls, the forma- 

 tion of any depOt, which could really be compared to an 

 atheromatous cyst of the skin, was altogether impossible. 

 The state of the matter here also is more or less very 

 simply this, that two processes must be distinguished in 

 the vessels, which are very analogous in their ultimate 

 results ; first, the simple fatty metamorphosis, which sets 

 in without any discoverable preliminary stage, and in 

 which the existing histological elements pass directly into 

 a state of fatty degeneration and are destroyed, so that a 

 larger or smaller proportion of the constituents of the 

 walls of the vessel perishes ; and, in the next place, a 

 second series of changes, in which we can distinguish a 

 stage of irritation preceding the fatty metamorphosis, 

 comparable to the stage of swelling, cloudiness, and en- 

 largement which we see in other inflamed parts. I have 

 therefore felt no hesitation in siding with the old view in 

 this matter, and in admitting an inflammation of the in- 

 ner arterial coat to be the starting point of the so-called 

 atheromatous degeneration ; and I have moreover en- 



