FIBROUS TISSUE. 693 



some fibres that were not previously observed may beeome 

 more distinct. The first kind does not refract the light 

 strongly ; the second kind does, showing some chemical 

 difterence in their composition. 



Cellular tissue, if dried, becomes a yellowish, brittle, 

 transparent mass ; but regains its former state if placed in 

 water. The fibres have a remarkable arrangement and 

 disposition. They are often deposited in a spiral manner; 

 at other times they are regularly undulating. In fibres 

 taken from some parts of the body, we find a fasciculus 

 Avound round in a spiral form. As a consequence, when 

 acetic acid is applied, we perceive projections of swollen 

 cellular tissue, and the depressions, from not having been 

 acted on, have a constricted appearance. The fibrous tissue 

 lining the eggshell, fig. 321, is the simplest form in which 

 it is found. 



Fat is generally found in the cellular tissue ; it is not 

 secreted from it, but is contained in its proper cells, and 

 termed adipose tissue ; the elementary cells of which are 

 from the 1 -300th to the 1- 600th of an inch in diameter 

 (fig. 3!i2). The cell-wall is very delicate and transparent; 

 sometimes there are one or two nuclei enclosed, ^ther 

 dissolves out the fat-cells from 

 the tissues. Acetic acid acts 

 upon the cell-wall, and causes 

 the contents to pass from within 

 outwards. 



Fibrous tissue, elastic and! 

 non-elastic, is usually divided 

 into white and yellow fibrous 

 tissue. The yellow is elastic, 

 and of great strength, consisting 

 of bundles of fibres which are' 

 highly elastic. (Fig. 324, ^o. 2.) 

 The white (fig. 324, No. 1), 

 though non-elastic, is of great 



^trPTiotVi and of a RhiniTio- ^^S- 322.— CeHs fmm adipose tissue, 

 Sirengm, ana OI a snimng, or /a«, magnified lOO diameters. 



silvery appearance. 



These two kinds of fibrous tissue differ from each other 

 in many respects, but chiefly in their ultimate structure, 

 their physical projDerties, and their colour : both are largely 



