coLuun J )i:( n:\JuUATioN 425 



Fiiclisin l)0(li(\s are foniid also in plasma cells and, less often, in other 

 cells, inelu(lin<>- granulation tissue; the fuchsin ])odies of this class are 

 believed 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 i)i"()(luc('(l by epitliclium, c. g., hyaline casts in the renal tu- 

 bules. 



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, ap- 

 parently derived from the chromatin, and a basic substance resem- 

 bling 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. Reckling- 

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

 coid degeneration. ^Nlarchand includes hyaline connective-tissue de- 

 generation, and, also, as do most other writers, the mucoid degeneration 

 of carcinoma. Ziegler rightly protests against the inclusion of mucin 

 under this heading, but includes the corpora amylacea. On account 

 of the discovery by Baumann of the specific chemical nature of thyroid 

 colloid it becomes particularly unfortunate that the term "colloid" 

 has such a wide and uncertain application. It would seem that the 

 safest view to take is that the word coUold is merely morpJiologically 

 and macroscopicaUii descriptive of certain products of cell activity or 

 disintegration, which have nothing in common except the fact that 

 they form a thick, glue-like or gelatinous, often yellowish or brownish 

 substance. There is no one definite suhstance colloid, according to 

 the usual usage of the word in pathological literature, but many dif- 

 ferent protein substances may assume the appearance to which the 



15 Jour. Exp. MecL, 1010 (12), 5,33. 



16 See discussion, Verh. Deut. path. Gesell., lOOS (12), 26.'S: :\liintcr, Virrhow's 

 Arch.. 1909 (198), 105. 



iGaBerl. klin. Woch., 1914 (51), 598. 



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

 (35), 259. 



