146 Connective Tissue (chap. 13) 



found by themselves. In most stains ground substance is imcolored, but 

 it contains mucopolysaccharides and can be shown by metachromatic 

 staining (page 280) . 



Hyalin(e) is a descriptive noun or adjective meaning glassy. A sub- 

 stance so described is a translucent, refractile albuminoid. Amyloid 

 deposits (amorphous material accmnulating in intercellular spaces in 

 certain pathologic conditions) is said to be hyaline in nature. Old 

 collagen can become hyaline. 



Fibrin (page 230) is formed from fibrinogen (a protein in blood 

 plasma) and as it forms develops a mesh of fibers at the site of cut blood 

 vessels. 



Mast cells are numerous in areolar and other types of connective 

 tissue. Staining of mast cells has been included with technics for cyto- 

 plasmic elements (page 276) because of their characteristic granules. 

 The cytoplasm of mast cells is stuffed with these granules that usually 

 are stained metachromatically. 



Plasma cells are more common in hemopoietic (concerned with blood 

 formation) tissue than in loose connective tissue and if numerous in the 

 latter appear to be associated with low-grade inflammation. 



Keratin is a horny material formed by the fusing together of the 

 surface cells of dry epithelial membranes. (Reference: Ham. 1957) 



Mallory Staining 



Mallory's Triple Connective Tissue Stain 



Innumerable modifications of this method appear from time to time 

 in the literature, partictilarly for the use of phosphomolybdic and phos- 

 photiuigstic acid. Experiments by Holde and Isler (1938) support the 

 need for phosphomolybdic acid if specific staining of connective tissue 

 is desired. The acid diminishes the backgroimd and nuclear staining, 

 leaving only the connective tissue stained with aniline blue. They feel 

 that the staining property of connective tissue is due to the presence 

 of the acid on the fibers. Baker (1938) suggests that phosphomolybdic 

 acid acts as a "colorless acid dye" in the tissue, chiefly on collagen. It 

 acts as a dye excluder with acid dyes such as acid fuchsin, excluding 

 them from collagen. Then the aniline blue stains the collagen selectively, 

 but is excluded from other tissues. Phosphomolybdic acid should not be 

 termed a mordant, since it also opposes the action of aniline blue. With- 

 out phosphomolybdic acid present, aniline blue stains more strongly 

 and with very little selectivity. As to the use of phosphotungstic acid. 



