FIBRILLAR CONNECTIVE TISSUE. 75 



tive tissue. The first effect of the acid, when applied at ordi- 

 nary temperatures, is that the tissue swells up to a great extent, 

 especially in the direction of the transverse diameter of the 

 fasciculi and fibrils. The latter, which are thus rendered less 

 strongly refractile, become so compressed against one another 

 with their glutinous surfaces, that their contours can no longer 

 be distinguished ; and in the transparent mass, as in boiled con- 

 nective tissue, new elementary forms now make their appear- 

 ance. Acetic acid is usually employed to produce this change, 

 and by this means to distinguish the fibrils of connective tissue 

 from those of other fibrous structures. 



Several other vegetable acids and diluted mineral acids, 

 especially hydrochloric acid of O'l per cent., and similarly 

 diluted nitric acid, act in the same manner as acetic acid. 



After treatment with acids, contractions resembling an hour- 

 glass frequently occur in the fasciculi of connective tissue, their 

 enlargement appearing to be prevented at certain points by a 

 firmly applied ligature. These are the much-discussed fasciculi 

 of connective tissue surrounded by coiled fibres. The appear- 

 ance of constrictions was formerly held to be due to spiral 

 fibres winding round the fasciculi, which, on account of their 

 not swelling in acetic acid, were considered to be of an elastic 

 nature.* 



At a later period attempts were made in various quarters to 

 support a view first advanced by Reichert/f which attributed 

 the contractions of the swollen bundles to the sheath of the 

 connective tissue being torn in the act of swelling up into loop- 

 like portions. The presence of such a sheath covering the fas- 

 ciculi in the form of a continuous membrane cannot, however, be 

 demonstrated in fresh fasciculi; we may, however, convince our- 

 selves of the presence of coiled fibres forming a plexus around 

 these, the fibres being sometimes finer and sometimes coarser. 

 On the cautious addition of alkalies to connective tissue swollen 



* Henle, Allgemeine Anatomic, Band cxcv., Jahreslericht fur 1857, p. 38. 



t Reichcrt, Miiller's Archiv, 1847. Leydig, Histologie des Menschen 

 und der Thiere. Frankfurt, 1857, p. 31. Klopsch, Muller's Archiv, 1858, 

 p. 417. Kolliker, Zeitschrift fur wissenschaftliche Zoologie, Band ix., 

 p. 140. 



I 



