GENERAL CONSIDERATIONS. 



T. THE EETKOGRADE METAMORPHOSIS AXD DEGENERATION 

 OF TISSUES.* 



§ (). The alterations to be considered in tlie first di^'ision of 

 this work have this feature in common, that the tissues which 

 •exhibit them have lost the wliole or a part of their significance 

 as livino; and functionallv active constituents of the or onanism. 

 The degree of this loss is different in each case. Some lead at 

 worst to a certain limited, though perhaps very considerable, 

 impairment of vitality, as, c.fj. amyloid degeneration and calci- 

 fication; others again, as, e.g. fatty metamorphosis, cause a 

 gradual but complete destruction of the independent life of the 

 affected tissue ; under this head, too, we may include necrosis 

 itself — i.e. the case in Avhich death precedes, instead of following, 

 the structural change. 



AYe will begin with the last-named process. 



1. Necrosis. 



§ 7. No sooner does that peculiar inter-dependence and 

 mutual connexion of the component parts of the human organ- 



* Nature begins lier labours with construction; we adopt the inverse 

 •order, taking first the decomposition of structures ah'cadj formed. This 

 is done for convenience sake. The reader is supposed to be famihar 

 with normal histology, with the materials on which the processes of 

 destruction and dissolution are exerted ; and, so far, it would seem to be 

 indifferent whether we choose to start from the progressive or the retro- 

 gressive series. Inasmuch, however, as we shall have to describe the 

 histological phenomena exhibited by morbid growths, such as cancer, 

 throughout their entire course, a previous acquaintance with many 

 processes belonging to the retrogressive series, such as fatty degenera- 

 tion, caseation, &c., is indispensably necessary. 



