78 



MANUAL OF HISTOLOGY. 



muscular substance already described. It will generally be 

 found that where this material occurs in bundles it is not be- 

 cause there are no meshes, but rather because they are com- 

 pressed laterally, so as not to be apparent unless most carefully 

 teased apart. When such fibres are broken off, their extremi- 

 ties curl up ; further, the fibres are unaffected by being boiled 

 in solutions of strong acids and alkalies, such as 35 per cent. 



FIG. 31. Elastic tissue networks. From the frog. 



solutions of caustic potash, or nitric acid (standard prepara- 

 tions commonly used in laboratories), unless the action is pro- 

 longed for a considerable time. These networks are beautifully 

 shown by taking the mesentery of the frog when slightly con- 

 tracted after immersion in acetic acid. The fibrillated connec- 

 tive tissue will then swell up and become invisible, while the 

 elastic fibres are unaffected. 



The ligamentum nuchse also affords an excellent oppor- 

 tunity for studying this tissue by itself. To render the work 

 more easy, the specimen may be allowecj. to soak a few days in 

 a 10 per cent, watery solution of common salt, so that it may 

 be the more easily teased. In the subcutaneous connective 

 tissue of the skin the elastic fibres are well shown by hferna- 

 toxylin preparations. Being unaffected by this staining solu- 

 tion they appear as bright, silk-like cords, which lie in close 

 apposition with the wavy bundles, and the branches arch over 

 the bundles, to anastomose with corresponding branches of 

 other bundles, so that in this way meshes are formed. Some 

 writers have spoken of little knobs at the nodal points of the 

 meshes, but these appearances have been illusory. 



Recklinghausen seems to have believed with Virchow, that 

 the elastic fibres contain peculiar nuclei of their own, which in 



