228 



ELASTIC FIBRES. 



tissue, the elastic fibres are exceedingly fine. In some animals elastic fibres are met 



with TsVoth of an inch in thickness. In shape they 

 are not cylindrical but angular, as is well seen in 

 transverse section (fig. 2G6). 



In certain portions of the areolar tissue, as for 

 instance in that which lies under the serous and 

 mucous membranes of particular regions, the yellow 

 or elastic fibres are abundant and large, so that they 

 cannot well be overlooked ; but in other parts and in 

 the fibrous tissue, they are few in number, and small, 

 and are then in a great measure hidden by the white 

 filaments ; in such cases, however, they can generally 

 be rendered conspicuous under the microscope by 

 means of acetic acid, which causes the white filaments 

 to swell up and become indistinct, whilst the elastic 

 fibres not being affected by that re-agent, come then 

 more clearly into view. 



Fig. 261. ELASTIC FIBRES FROM THE 



LIGAMENTA SUBFLAVA ; MAGNI- 

 FIED ABOUT 200 DIAMETERS. 



(Sharpey. ) 



Watery solutions of magenta and many other aniline dyes 

 stain elastic fibres very intensely. Elastic fibres do not yield 

 gelatine on boiling. They are composed of a substance 

 named elaxtin, which is enclosed in a membrane or sheath 

 (Schwalbe). This membrane resists the action of digestive 

 ferments, and also that of acids and alkalies, which break 



the elastin up into globules and eventually dissolve it (Pfeuffer, Mall). According to Mall 

 this membrane is chemically similar to the reticulum of retiform tissue. 



Many observers have described transverse striation in elastic fibres (see fig. 265), especially 

 in those that have been long macerated. It is not improbable that appearances of transverse 



Fig. 262. SUBCUTANEOUS AREOLAR TISSUE FROM A YOUNG BABBIT. HIGHLY MAGNIFIED. (E. A. S. ) 



The figure shows the appearance of the tissue examined perfectly fresh in a preparation made by 

 the demi-dessication method and moistened only with lymph. 



The white fibres are in wavy bundles, the elastic fibres form an open network, p, p, vacuolated 

 cells (plasma cells) ; g, granular cell ; c,c, branching lamellar cells ; c', a flattened cell of which only 

 the nucleus and some scattered granules are visible ; /, fibrillated cell. 



Drawn under Zeiss' 2 mm. apochromatic homogeneous-immersion objective, and No. 8 compensating 

 eyepiece. 



