426 ATHEKOMA. 



cyst], had been assigned. It is self-evident, therefore, that the idea of 

 atheroma presupposes a closed sack. Nobody ever called anything in 

 the skin an atheroma that lay open and uncovered. It was therefore a 

 curious misapprehension when people recently began to call changes in 

 the vessels atheromata, which were not seated below the surface and 

 shut off from the surrounding parts, but belonged to the surface. Thus 

 it has come to pass that, instead of an enclosed deposit being, in accord- 

 ance with the original meaning of the term, called atheromatous, a 

 change has frequently been so termed which commences quite at the 

 surface of the internal arterial coat. When the matter began to be 

 examined more minutely, and fatty particles were found at very different 

 points in the walls of the vessel, both when atheroma was, and was not, 

 present when at last the conviction was obtained, that the process of 

 fatty degeneration was always the same and was identical with the 

 atheromatous change, it became the custom to unite all the forms of 

 the fatty degeneration of arteries under the designation atheroma. 

 Gradually, people even came to speak of an atheromatous change in 

 vessels, that only possessed a single coat, for in them too we meet with 

 fatty processes. 



" At all times there have, moreover, been observers who regarded the 

 ossification of vessels as a change belonging to the same category as 

 atheroma. Haller and Crell believed that the ossification proceeded 

 from the atheromatous 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 recognised that athero- 

 masia 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 atheromatous change and 

 the ossification proceeded. But, instead of this, the track of fatty 

 degeneration was pursued, and thus the atheromatous process was ex- 

 tended to a number of vessels, in which, on account of the thinness and 

 the simple structure of their walls, the formation of any de"p6t, which 

 could really be compared to an atheromatous cyst of the skin, was alto- 

 gether 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 



