THE DIGESTIVE APPARATUS. 141 



in the mean time, given off their mucine as a secretion. A 



granular protoplasmatic substance now fills the altered cell 

 body. 



m& 



Fig. 132. — Submaxillary gland of the dog, with its contained cells ; a, changed by the strong 

 irritation of the chorda ; I', those remaining unchanged (after Heidenhain). 



This was altogether the first difference which a quies- 

 cent and active gland presented to the eye of the micros- 

 copist. 



The parotid gland contains in its acinus (measuring 0.034 

 to 0.052 mm.), granular cubical cells (of 0.014 to 0.018 mm.), 

 without any mucous metamorphosis. Fine secretory tubes 

 have been met with between the latter. Here, again, the ex- 

 cretory duct has ordinary cylinder cells. 



The tongue is an essentially muscular organ, with transverse- 

 ly striated filaments crossing each other. The dorsum of the 

 tongue has innumerable different papillae. Three forms have 

 been distinguished here : the filiform (papillae filiformes, s. 

 conicae), the fungiform (p. fungiformes, s. clavatae), and, finally, 

 the circumvallated (p. circumvallatae). To the latter have also 

 been added the so-called papillae foliatae, which were early 

 discovered, then forgotten, and recently more accurately in- 

 vestigated. Both the latter organs contain the terminations 

 of the gustatory nerves. 



Our organ is rich in racemose glands. We meet principally 

 with mucous glands, with the contents rendered familiar to us 

 by Fig. 130. In the vicinity of the p. circumvallata and the 



