42 



HANDBOOK OF PHYSIOLOGY. 



The fibres composing the former are of two kinds (a.) White fibre:* 

 (b.) Yellow elastic fibres. 



(a.) White Fibres. These are arranged parallel to each other in wavy 

 bundles of various sizes: such bundles may either have a parallel ar- 



Fig. 37. 



Fig. 38. 



Fig. 39. 



Fig. 37. Ramified pigment cells from the tissue of the choroid coat of the eye. X 360. a, Cell 

 with pigment; b, colorless fusiform cells. (Kolliker.) 



Fig. 38. Flat, pigmented, branched connective-tissue cells from the sheath of a Karge blood- 

 vessel of the frog's mesentery: the pigment is not distributed uniformly throughout the substance 

 of the larger cell, consequently some parts of it look blacker than others (uncontracted state). In 

 the two smaller cells most of the pigment is withdrawn into the cell-body, so that they appear 

 smaller, blacker, and less branched, x 350. (Klein and Noble Smith.) 



Fig. 39. Fibrous tissue of cornea, showing bundles of fibres with a few scattered fusiform cells 

 (A) lying in the inter-fascicular spaces. X 400. (Klein and Noble Smith.) 



rangement (fig. 39), or may produce quite a felted texture by their inter- 

 lacement. The individual fibres composing these fasciculi are exceedingly 

 fine, varying from T of rs - to irdnnr incn > *> Wcnr to roVcr mm./ or 0.5 to 



I//, homogeneous, unbranched, and of the 

 same diameter throughout. They can readily 

 be isolated by macerating a portion of white 

 fibrous tissue (e.g., a small piece of tendon) 

 for a short time in lime, or baryta-water, or 

 in a solution of common salt, or of potassium 

 permanganate: these reagents possess the 

 power of dissolving the cementing inter- 

 fibrillar substance and of thus separating the 

 fibres from each other. By prolonged boil- 

 ing the fibres yield gelatin. 



(b.) Yellow Elastic Fibres (fig. 40) are of 

 all sizes, from excessively fine fibrils, ^5^-5^ 

 inch, up to fibres of considerable thickness, 

 46 1 00 inch (i.e., from about \n to 6/j.) : they 

 are distinguished from white fibres by the 

 following characters: (1.) Their great power 

 of resistance even to the prolonged action of chemical reagents, e.g., 

 caustic soda, acetic acid, etc. (2.) Their well-defined outlines. (3.) 



millimetre = 1 micron, which is represented by the Greek /*. 



Fig. 40. Elastic fibres from 

 the ligamenta subflava. x 200. 

 (Sharpey.) 



