X.] 



CONNECTIVE TISSUE. 



157 



but in the plasma cells the protoplasm is vacuolated, and the 

 vacuoles contain fluid. They sometimes have short processes. 

 What the relation of the clasmatocytes to these other cells may be 

 is so far not determined ; nor, indeed, do we know the relation 

 between the granular and the plasma cells. 



The migratory cells are identical with the white blood-cor- 

 puscles or lymph-corpuscles, and may therefore be regarded as an 

 adventitious element. 



Yellow or Elastic Fibres occur in the ligamentum nuchse of 

 animals (large fibres) ; lig. subflava ; stylo-hyoid ligament ; con- 

 nective tissue generally ; in the walls of the air-tubes and lungs ; 

 the larger blood-vessels, especially arteries ; the vocal cords and 

 some ligaments of the larynx ; many organs, e.g., spleen. 



1. Yellow or Elastic Fibres Thick Fibres (H). Tease out 

 in water a fragment of the ligamentum nuchse of an ox ; cover 

 and examine it. It can be mounted in Farrant's solution. 



(a.) Observe the broad 

 fibres with a definite 

 outline, yellow in colour, 

 refracting the light 

 strongly, branching and 

 anastomosing, and some- 

 times curling at their 

 ends where they are 

 broken across (fig. 120, 

 /). A small quantity 

 of white fibrous tissue 

 will be found between 

 and supporting the 

 ill .res (/,). 



(/>.) Measure the size 

 of one of the larger 

 fibres. They are about 

 7_8 /A (;nWth m ch) in 

 diameter. 



((-.) Irrigate with acetic 

 acid. The fibres are not affected, and no nuclei are revealed in 

 them. They consist of the substance elastin, which is unaffected 

 by acetic acid. 



Make longitudinal and transverse sections of the ligamentum 

 nuchse (hardened in alcohol). Stain both in picro-carmine and 

 mount in Farrant's solution. The connective tissue is thereby 

 stained red, and the elastic fibres yellow. 



2. L. S. Ligamentum Nuchae (H). Observe the fibres (yellowish), 

 with a small amount of connective tissue (red) between them. The 



FIG. 120. f. Elastic fibres from the 

 undue ; f>. Fine white fibrous tissue, x 300. 



