THE TONGUE IN THE HORSE. 19 



palate forms a curtain interposed between the cavity of the 

 mouth and the cavities of the nose. In short, it is a valve 

 having the effect of cutting off the communication between 

 the posterior nostrils and the cavity of the mouth. This veil 

 or valve gives passage to the masticated food backwards into 

 the pharynx, but at other times lies so close on the back 

 part of the epiglottis or lid of the larynx, that the air from 

 and to the windpipe in respiration does not pass through the 

 mouth, but only through the nostrils. In like manner, when 

 it happens, which is rare, that the horse rejects the contents 

 of the stomach upwards, the rejected matter does not issue 

 through the mouth, as in animals that vomit, but through 

 the nostrils. The veil of the palate is composed of mucous 

 membrane enclosing muscular fibres. 



Tongue. The tongue occupies the floor of the mouth. It lies 

 between the nearly parallel sides of the lower jaw, and thus 

 has the chief share in filling up the void between these. Those 

 portions of the tongue which, in the language of anatomy, 

 are free that is, unadherent to adjacent parts are covered 

 by mucous membrane. The whole of the upper surface and 

 its margins, from the epiglottis or lid of the larynx to the 

 tip, are free also the anterior part of the under surface. 

 The substance of the tongue is muscular that is, fleshy. 

 A considerable portion of the tongue is made up of muscu- 

 lar fibres, which are confined within the limits of the organ. 

 Other sets of muscular fibres come from adjacent parts, and, 

 running into its substance, increase its bulk. Those muscular 

 fibres which extend from adjacent points necessarily enter the 

 tongue by those parts of its surface which are not free namely, 

 its base, and the posterior part of its under surface. The mus- 

 cular fibres which do not extend beyond the limits of the 

 organ, serve principally to alter its form for example, to curve 

 the tip of the tongue upwards, or to curve its tip downwards. 



