STRUCTURE OF THE TONGUE. 463 



of muscles, which are continued into its substance. This con- 

 nexion is such, that the edges of the tongue are perfectly free 

 and unconnected ; and so is the anterior extremity for a con- 

 siderable distance from the apex towards the base. 



The substance of the tongue consists principally- of muscu- 

 lar fibres intermixed with a delicate adipose substance. It is 

 connected to the os hyoides by the hyo-glossus muscle, and also 

 by some other muscular fibres, as well as by a dense mem- 

 branous substance, which appears to perform the part of a 

 ligament. This connexion is also strengthened by the con- 

 tinuance of the integuments from the tongue to the epiglottis 

 cartilage, to be hereafter described ; for that cartilage is attached 

 by ligaments to the os hyoides. 



The tongue is thin at its commencement at the os hyoides ; 

 but it soon increases in thickness. The muscular fibres in its 

 composition have been considered as intrinsic, or belonging 

 wholly to its internal structure ; and extrinsic, or existing in 

 part outside of this structure. The lingualis muscles are 

 intrinsic (see page 316) : they are situated near the under sur- 

 face of the tongue, one on each side, separated from each other 

 by the genio-hyo-glossi muscles, and extending from the basis 

 of the tongue to its apex. These muscles can be easily traced as 

 above described : but there are also many fibres in the structure 

 of the tongue, which seem to pass in every direction, and of 

 course are different from those of the linguales muscles. To 

 these two sets of fibres are owing many of the immensely 

 varied motions of the different parts of the tongue. 



According to Gerdy, (whose researches on this subject 

 have been approved by Ribes and Breschet,) the structure of 

 the tongue consists of the mucous membrane forming its outer 

 coat, of a peculiar yellow lingual tissue ' which forms the liga- 

 ment by which it is attached to the os hyoides and is extended 

 along the middle line of the tongue to form a sort of raphe for 

 the attachment of the transverse muscular fibres, and of the 

 intrinsic and extrinsic muscles ; it is mixed up with some delicate 

 cellular and adipose tissue. The intrinsic muscles consist, 1st, 

 of a superficial lingual muscle ; 2d, of two deep-seated, all of 



