196 ANATOMY OF THE HEAD. 



ever, some fat is generally intermixed. The tongue is fixed 

 at its base to the most forward portion of the os hyoides, 

 to which many of its muscles are attached. The muscles 

 of the tongue will not account for all the motions of that 

 organ ; that is, if we give to muscles no other property 

 than that accorded to them by the generality of anatomists, 

 viz. contraction. How are we, according to this version, 

 to account for an organ formed almost wholly of muscular 

 fibre, being propelled out of the mouth, or elongated and 

 turned in various directions. We know by feeling the arms 

 of men, but more so by feeling the limbs of animals when 

 spasmodically affected, that muscle, when contracted, can 

 become almost of the firmness of metal or of bone. May 

 not a texture, which has the powder of assuming this pro- 

 perty of rigidity, be also capable of dispensing wdth bone ; 

 and be gifted with a faculty of extension as well as contrac- 

 tion ? Grant this, which assumption the tongue appears to 

 necessitate, for its rightful interpretation, and the entire 

 difficulty is conquered. 



This subject of the protrusion of the tongue is little 

 understood. Muscular fibre, however, must act upon every 

 substance, whether it be bone or not, with which it is in 

 contact. Thus much glandular matter and some fat inter- 

 mingling with the muscles of the tongue ; and such sub- 

 stances being pliable, but not compressible it is easily 

 understood how pressure might make them assume another 

 form, and become long, wdiereas they were originally broad. 

 The HYO GLOSsus BREVis, wliicli appears always to act with 

 its fellow^ at the back of the tongue, has no lateral motion. 



The LONGUS is the main agent in retracting it ; when one 

 muscle alone acts the tongue w^ould be drawn to one side. 

 The LONGUS is likewise the means by which the tongue is 

 curved downwards. The muscle which twines the tongue 

 upwards is the genio hyo glossus, whose fibres run from 

 the front of the os hyoides to the point of the low^er jaw. 



The BREVIS, aided by its accessories and the lingualis, 

 pulls downward the back of the tongue ; thus forming a 

 vacuum which draws water wuthin the mouth, or performs 

 the office of suction. The reason of so many muscles being 

 crowded together for the motion of the tongue, is the 

 extent of surface to be moved ; the power required to move 



