WITH THE MICROSCOPE. I 19 



beautiful manner. It consists of two elementary tissues the ic.' 

 fibrous tissue and the yellow fibrous or elastic tissue ; but it is often 

 associated with adipose tissue, and in it vessels, nerves, and frequently 

 lymphatics ramify. 



The structure of areolar or connective tissue may be well studied 

 in pieces removed from beneath the mucous membrane of the back 

 of the tongue or throat, or in that which connects the mucous mem- 

 brane of the stomach and intestine with the muscular coat. By 

 staining carefully, the germinal matter (nuclei) of the white fibrous 

 tissue, of the yellow elastic tissue, of capillaries, and nerve fibres may 

 be distinguished. It is, however, better to prepare it according to 

 the plan given in detail in part V. 



254. White Fibrous Tissue can be readily obtained free from the 

 yellow element in tendons and many fasciae. In the former, its fibres 

 are slightly wavy, but parallel to each other. It can be split up in- 

 definitely, and does not appear to be composed of minute fibres. This 

 fibrous appearance is destroyed by the action of acetic acid and 

 alkalies, and is rendered less distinct if the tissue be soaked in glyce- 

 rine. Upon the addition of water, the tissue resumes its ordinary 

 appearance. White fibrous tissue is very opaque, and in order to 

 demonstrate its characters well, it is desirable to cut a very thin 

 section, unravel it with needles, and subject it to moderate pressure 

 under the thin glass. In pi. XXVI, fig. 169, a portion of tendon is 

 represented without its nuclei. 



215. Yellow Fibrous Tissue may be obtained, perfectly free from 

 the white fibrous element, from the ligamentum nuchce, a firm yellow 

 cord at the back of the neck, of any animal, from arteries, or from 

 the elastic ligament to which the retraction of the claw in the cat 

 and other feline animals is due. It consists of circular fibres dis- 

 posed to curl up very much, and not easily broken or destroyed by 

 the action of reagents. In areolar tissue the fibres are very long and 

 branching, after the manner of a network ; in the ligamentum nuchas 

 they are parallel to each other, pi. XXVI, fig. 170 : in the longitu- 

 dinal fibrous coat of the arteries they are parallel and extremely 

 delicate ; in the circular coat they are coarse, and the material is 

 often disposed in ragged laminae rather than in distinct fibres. 



The germinal matter (nuclei) of both white and yellow fibrous 

 tissue may be demonstrated according to the method of investiga- 

 tion described in part V. Notice also figs. 167, 168, pi. XXVI. 



2K6, Adipose Tissue. Adipose tissue maybe examined by cutting 

 off a thin section, and placing it with a little water between two 

 pieces of glass, care being taken not to allow the thin glass cover to 

 press upon it. The surface of one of the smallest collections of fat 



