RETICULAR AND OTHER CONNECTIVE TISSUES 281 



one sometimes encounters difficulties in the transition from the 

 fibrous perichondrium to the cartilage matrix. 



The distribution of the fibers blackened by silver is so extensive 

 that one is tempted to question the selective action of the method. 

 They are encountered in all the lymphoid organs, in the mucosa 

 of the digestive tract, in and about the walls of the lymphatics 

 and blood-vessels, in the framework of all the secreting glands, 

 e.g., liver, salivary glands, pancreas, mucous glands of the respir- 

 atory and digestive tracts, in the kidneys, ovary, uterine wall, 

 testis, prostate, sweat glands, in the corium of the skin, in the 

 tunicae propriae of the respiratory and digestive apparatus, 

 about the glands of the gastro-intestinal mucosa, and to a limited 

 extent among the fibers of areolar and collaginous tissue wherever 

 it is found. Many of the basement membranes consist largely 

 of these argentiferous fibers. 



If one is careful not to overtone the specimens the results in 

 mature tissues are fairly constant; in such preparations (with a 

 few reservations) the method appears quite definitely selective 

 for the blackened fibers of reticular tissue ("reticulum." Mall), 

 the elastic and fibroglia fibers remain colorless and the collaginous 

 fibers assume a brownish tint. 



This result was arrived at by a careful comparison of the effect 

 of this and other stains upon the several tissues in locations where 

 each is known to occur. The conclusions are based on the fol- 

 lowing observations. 



A. ELASTIC FIBERS 



Sections of the ligamentum nuchae after impregnation show the 

 elastic fibers absolutely colorless and outlined by an intense black 

 fibrous mass which occupies nearly the entire non-vascular area 

 between the elastic fibers, and which at the borders of the elastic 

 bundles shades into the golden brown of the collaginous fibers 

 forming the coarse bands of the framework (fig. 1). In the con- 

 trols the elastic fibers show the characteristic staining reaction 

 with hematein and eosin and with Van Giesen's stain, and the 

 intervening tissue is colored red by eosin and by acid fuchsin. 



THE AMERICAN JOURNAL OF ANATOMY, VOL. 12, NO. 3 



