158 



PRACTICAL HISTOLOGY. 



[X. 



lil)res ; c. Connective-tissue 

 between them; n Nuclei 

 of connective-tissue cor- 

 puscles. Alcohol and borax- 

 carmine, x 300. 



fibres are broad with well-defined margins, have a feeble yellow 



tint, and are transparent. They branch and anastomose, and where 



ruptured curl up at their ends. 



3. T.S. Ligamentum Nuchse of Ox (H). Observe the polygonal 



ends of the broad fibres yellow and nearly as broad as, or broader 

 than, a coloured blood-corpuscle, sometimes 

 single, mostly in groups of three or more 

 (fig. 1 2 1, a) homogeneous throughout. A 

 small amount of connective tissue (c) (red) 

 between the groups. 



4. Another section may be stained with 

 a watery solution of magenta and mounted 

 in Farrant's solution. The fibres are stained 

 red, but the pigment is ap6 to diffuse into 

 the Farrant's solution. 



5. A good plan is after hardening the 

 ligamentum nuchse in alcohol to stain it in 

 borax-carmine for several days, with the 



precautions stated at p. 65. Transverse sections show the white 

 fibrous tissue between the elastic fibres, with its nuclei stained red 

 (fig. 121, n). 



6. Fine Yellow Elastic Fibres (H). Harden the mesocolon or 

 mesentery of a young rabbit in Flemming's fluid, and stain it in 



methyl-violet as directed under Lesson X. 14, 



^^^^^^^^^ or stain it with magenta, when the elastic 

 fibres are stained red ; or with safranin after 

 hardening in chromic acid. 



(a.) Observe the network of fine elastic 

 fibres. Many of the fibres have a diameter 

 equal to one-sixth, or less, of that of a 

 coloured blood-corpuscle (i p. or TT^.^Q- inch 

 Mesocolon of Rabbit, in diameter). The fibres branch and anasto- 



J lemming s fluid and j i r 1 1 j? 



safranin. mose, and by carefully focussing, one can 



observe that the fibres do not all lie in 

 the same plane (fig. 122). 



7. Fenestrated Membranes (H). Sometimes the elastin is so 

 arranged as to form sheets or plates of elastic tissue, e.g., in the 

 large arteries ; at other times these are perforated with holes, and 

 are called fenestrated elastic membranes. 



With a pair of forceps tear off a little of the endocardium from a 

 sheep's heart, spread it on a slide, and treat it with caustic potash. 

 Or use the basilar artery, slit it up and scrape away the outer coats, 

 and use caustic potash as before. 



(a.) Observe near the margin of the preparation the elastic 

 membrane with holes in it (lig. 123). 



