HYALINE DEGENERATION 353 



HYALINE DEGENERATION 1 



Much confusion concerning this condition may be avoided if 

 we appreciate that the term hyaline indicates a certain physical 

 condition, which may be exhibited by many substances of widely 

 different nature and origin. There is no one chemical compound, 

 " hyalin" which, accumulating in cells or tissues, produces a 

 hyaline appearance. The limits of the application of the term 

 " hyaline degeneration," even to histological findings, is not 

 agreed upon, but in general it is used to apply to clear, homo- 

 geneous, pathological substances that possess a decided affinity 

 for acid stains, such as eosin or fuchsin. Somewhat similar 

 substances, usually of epithelial origin, which do not take either 

 these or basic stains strongly, are usually called "colloid." 

 We may properly consider that pathological hyalin can be 

 divided into two chief classes according to its origin : (1) con- 

 nective-tissue hyalin ; (2) epithelial hyalin. 



Connective-tissue hyalin is characterized, like amyloid, 

 by being deposited in or among the fibrillar substance of con- 

 nective tissues, and not within the cells themselves, but there 

 are undoubtedly several different sorts of chemical substances 

 responsible for various forms of connective-tissue hyalin. One 

 form is closely associated with amyloid, being found in organs 

 showing amyloid degeneration, or in other tissues in the same 

 body. In experimentally produced amyloidosis in animals it 

 has been shown that such a hyaline substance may appear before 

 the amyloid, which eventually replaces it ; hence, it has been 

 suggested that hyalin is a precursor of amyloid. Such hyalin 

 differs from true amyloid only in its failure to give the 

 characteristic staining reaction of amyloid ; in all other respects, 

 e. g., cause, location, termination, it is the same. As it has 

 been shown (see preceding section) that the staining properties 

 of amyloid are very inconstant, it is probable that the above- 

 described variety of hyalin is merely an incompletely developed, 

 or occasionally a retrogressively altered amyloid. However, it 

 is probably not necessary, as some authors have thought, that 

 amyloid should always pass through this hyaline stage in its 

 formation. 



Quite different, without doubt, is the form of hyalin observed 

 in scar tissue. This variety develops almost constantly in any 

 scar-tissue after the blood-supply has been reduced to a mini- 

 mum through contraction, and is seen characteristically in the 

 corpora fibrosa of the ovary, fibroid glomerules in chronic 



1 General literature, see Lubarsch, Ergeb. allg. Path., 1897 (4), 449. 

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