THE DIGESTIVE TRACT. 



157 



The blood- supply of the tongue is very rich, the vessels forming 

 a superficial net-work in the mucosa, from which minute twigs as- 

 cend within the papillae to terminate at the summit in close capillary 

 plexuses. 



The acini of the various glands are surrounded by capillaries, as 

 are also the lymph-follicles through the adenoid tissue of which many 

 minute vessels extend. The capillary net-works supplying the mus- 

 cular tissue follow the general arrangement and direction of the mus- 

 cular fibres, surrounding the latter by the characteristic rectangular- 

 meshed net-works. 



The lymphatics of the tongue are numerous ; they are arranged 

 as a superficial plexus within the submucous tissue, which re- 

 ceives the lymphatics from 



the bases of the papillae ; the FIG- 193- 



latter vessels, in turn, take up 

 the smaller trunks having their 



FIG. 192. 



Section of tonsil of dog : a, epithelium of 

 mucous membrane passing into central recess 

 (6), where it becomes infiltrated with lymphoid 

 cells (e) ; c, lymph-nodules embedded within 

 diffuse adenoid tissue ; d, neighboring mucous 

 glands. 



Section of tonsil of child ; the epithelium of adja- 

 cent surface passes into the deep pits which extend 

 into the adenoid tissue. 



origin in the numerous interfascicular lymph-spaces within the cen- 

 tral papillary connective tissue. The lymph-follicles at the root of 

 the tongue are well provided with lymphatics, which surround the 

 follicles and give off radicles to the adenoid tissue. 







