COLLOID DFXiENERATION 429 



tissue stains. Presumably (his I'oiiii ol" hyalin is an increased and 

 physically altered elastin.**- 



Epithelial hyalin occurs within the cells, and includes substances 

 of presumably widely diverse chemical nature, from the keratin of 

 squamous epithelium to the small intracellular hyahne granules of 

 carcinoma and other degenerating cells (Russell's fuchsin bodies)/'^ 

 Fuchsin bodies are found also in plasma cells and, less often, in other 

 cells, including granulation tissue; the fuchsin bodies of this class are 

 beheved by Brown^^ to be derived from red corpuscles, a view also 

 held by Saltykow, but not accepted by all pathologists/'^ Extracellu- 

 lar substances of hyaline character, but of unknown composition, may 

 also be produced by epithelium, e. g., hyaline casts in the renal 

 tubules. 



The composition of none of these forms of hyalin is known, except 

 that by using microchemical methods Unna®® has found evidence that 

 keratohyalin consists of two elements, one of acid character, appar- 

 enth' derived from the chromatin, and a basic substance resembling 

 the globulins. 



Many other pathological materials of widely differing nature may, 

 under certain conditions, assume a hyaline appearance; e. g., fibrinous 

 exudates and thrombi, degenerated muscle-fibers (Zenker's or "waxy" 

 degeneration), tumor-cells, (cylindroma), etc. In all of these the 

 chemical nature of the parent substance or substances is probably 

 much less altered than its physical appearance, but whether the change 

 is related to the process of protein coagulation or not is unknown. 

 Occasionally hyalin, both in epithelium and connective-tissue, takes 

 on a crystalline structure (Freifeld).^^ 



COLLOID DEGENERATION 



This term, also, has a very indefinite meaning, and is applied to 

 many different conditions by various authors. Thus, v. Reckhng- 

 hausen includes under this name amyloid, epithelial hyaline, and mu- 

 coid degeneration. Marchand includes hyaline connective-tissue 

 degeneration, and, also, as do most other writers, the mucoid degenera- 

 tion of carcinoma. Ziegler rightly protests against the inclusion of 

 mucin under this heading, but includes the corpora amylacea. On ac- 

 count of the chscovery by Baumann of the specific chemical nature of 

 thyroid colloid it becomes particularly unfortunate that the term 

 ''colloid" has such a wide and uncertain apphcation. It would seem 

 that the safest view to take is that the word colloid is merely morpho- 



" See Schmidt, Verb. Deut. path. Gesell., 1904 (7), 2. 



*^ Literature, see Hektoen, Progressive Med., 1899 (ii), 241. 



6* Jour. Exp. Med., 1910 (12), 533. 



«5 See discussion, Verh. Deut. path. Gesell., 1908 (12), 265; Miinter, Virchow's 

 Arch., 1909 (198), 105. 



« Berl. klin. Woch., 1914 (51), 598. 



"Ziegler's Beitr., 1912 (55), 168; also Goodpasture, Jour. Med. Res., 1917 

 (35), 259. 



