FATTY DEGENERATION. 359 



whilst the others remain almost intact. Then indeed a 

 softening really does occur, but such a minute one, that 

 it is altogether imperceptible to the naked eye and can 

 only be demonstrated microscopically. In this case we 

 generally make use of the expression, atrophy of muscle, 

 although the process which has attacked the individual 

 primitive fasciculi, does not in any way differ in its na- 

 ture from the processes which we at other times term 

 softening of muscle. 



This is the reason, why the term softening, which must 

 be reserved for coarse pathological anatomy, cannot sim- 

 ply be applied to histological processes, and why it is 

 better to say necrobiosis, when we have to do with these 

 more delicate processes. The common feature of all the 

 varieties of the necrobiotic process is, you know, that the 

 affected part at the close of the process is destroyed, nay 

 annihilated. 



A second class of passive processes is formed by the 

 simply degenerative forms, in which, at the conclusion of 

 the process, the affected part is in some condition or other 

 less fitting it for action, and has generally become more 

 rigid. This group might therefore be termed hardenings 

 (indurations) and thus a group be formed distinguishable 

 even externally from the necrobiotic processes. Only 

 the term induration also would easily be misunderstood, 

 inasmuch as in this class likewise many conditions occur, 

 in which the hardness of the organ on the whole at least 

 does not become more considerable, but only isolated, 

 very minute parts undergo change, so that no very strik- 

 ing effects are apparent to the sense of touch. 



Allow me now to hold up to you as types a few of the 

 processes belonging to this class, which are of the great- 

 est importance in a directly practical point of view. 



Among the necrobiotic processes the one which is un- 



