CARIES. 463 



went transformation itself, also determined the surround- 

 ing parts to enter upon the change. These are the 

 processes, without the aid of which it is impossible to 

 comprehend the history of caries. For the whole essence 

 of caries consists in this : the bone breaks up into its ter- 

 ritories, the individual corpuscles undergo new develop- 

 mental changes (granulation, suppuration), and remnants * 

 composed of the oldest basis-substance remain in the form 

 of small, thin shreds in the midst of the soft substance. 

 I traced this out again only to-day in a stump, in which, 

 a fortnight after amputation, periostitis with slight sup- 

 puration and incipient peripheral caries was found to 

 exist. When in such a case the thickened periosteum is 

 stripped off, we see, at the moment it quits the surface 

 and the vessels are drawn out from the cortex of the bone, 

 not, as in normal bone, mere threads, but little plugs, 

 thicker masses of substance ; and if they have been 

 entirely drawn out, there remains a disproportionately 

 large hole, much more extensive than it would be under 

 normal circumstances. On examining one of these plugs 

 you will find that around the vessel a certain quantity of 

 soft tissue lies, the cellular elements of which are in a 

 state of fatty degeneration. At the spot where the vessel 

 has been drawn out, the surface does not appear even, as 

 in normal bone, but rough and porous, and when placed 



* In ossification (in cartilage) there is a portion of the original intercellular sub- 

 stance of the cartilage that, namely, which lies between the large groups of carti- 

 lage-cells (secondary cells Tochterzellen) which, though it belongs to the groups 

 as wholes, yet when these, in the course of ossification, are transformed into a num- 

 ber of isolated bone-cells, becomes, comparatively speaking, almost entirely inde- 

 pendent of these cells individually (which have their own immediate intercellular 

 substance to attend to, and from most of which it must be separated by a considera- 

 ble interval), and therefore escapes the changes which befall them. It is this 

 portion (well shown in Fig 126, where it is represented by the trabeculae separating 

 the medullary spaces m), which remains behind in caries, whilst the secondary inter- 

 cellular substance perishes. In other processes, however, which run a more chronic 

 course (in cancer, for example), everything is destroyed. Based upon MS. notes by 

 the Author. 



