i 7 8 



ELEMENTS OF HISTOLOGY, [chap. xxn. 



same changes of growth as the enamel organ of the 

 milk tooth did in the first period of foetal life. A 

 new tooth is thus formed in the depth of the alveolar 

 cavity of a milk tooth, and the growth of the former 

 in size and towards the surface gradually lifts the 

 latter out of its socket. 



CHAPTER XXII. 



THE SALIVARY GLANDS. 



238. THE salivary glands, according to their 



structure and secretion, are of the following kinds : 



(1) True salivary (Fig. 106), serous, or albuminous 



Fig. 106. From a Section through a Serous or True Salivary Gland ; 

 part of the Human Sub-maxillary. 



a, The gland alveoli, lined with the albuminous " salivary cells ; " 6, intralobular 

 duct cut transversely. (Atlas.) 



