SALIVARY GLANDS. 65 



quite clear, with its small nucleus near the alveolar wall. Study the lunate cells or crescents 

 of Gianuzzi. (Indicate the alveoli, the cells lining than, and a lobar duct in PI. XIII., Fig. i.) 



Sub-maxillary Gland of a Rabbit: EXAMINATION (L). Observe the same general 

 characters. 



(H). Study an Alveolus. Observe the small lumen and the single layer of low columnar 

 cells lining it. Compare it with the above description. 



TONSILS. 



The tonsils are folds of mucous membrane containing a large number of lymph-follicles 

 like those composing a Peyer's patch (p. 69). The mucous membrane is folded so as to 

 eave pits or depressions visible on. the surface. The epithelium covering them is stratified, 

 and under it is a connective-tissue mucosa, which contains the closely aggregated masses of 

 adenoid tissue. 



PREPARATION. Harden the tonsils for two weeks in chromic acid and spirit mixture, or 

 in Miiller's fluid for three weeks. Make transverse sections, stain with logwood, and mount 

 in dammar. 



EXAMINATION (L). Note the stratified epithelium, and under it the oval or rounded 

 masses of adenoid tissue, which sometimes penetrate into the epithelium. 

 (H). The ordinary structure of adenoid tissue. 



OESOPHAGUS. 



PREPARATION. Slightly distend the oesophagus of a dog with the chromic acid and spirit 

 mixture, and keep it distended by placing a ligature on its upper and lower ends. Suspend it 

 in a large quantity of the same fluid until it is ' fixed ' i.e. for twenty-four hours then cut it 

 into pieces one inch long and continue the hardening for a week or ten days. Make transverse 

 sections through the upper and lower parts of the oesophagus. Stain them with picrocar- 

 mine, and mount in Farrant's solution. 



Transverse section of the (Esophagus. EXAMINATION (L). Observe the mucous coat 

 lined by stratified epithelium with well-marked mucous glands opening on its surface. The 

 mucous membrane is beset with small papillae. In the deeper part of the mucous coat observe 

 the cut ends of the muscularis mucosze, composed of non-striped muscular tissue arranged in 

 bundles. In the sub-mucous coat observe the alveoli of the mucous glands and trace a duct 

 to the surface. Observe the muscular coat the outer or longitudinal layer cut transversely, 

 and the circular fibres inside it. These contain much striped muscle in the upper part of the 

 oesophagus. 



(H). Study the stratified epithelium and the mucous glands, which are exactly like those 

 already described in the mouth (p. 61). A preparation mounted in dammar shows their 

 ' mucous ' characters admirably. 



Nerves of the (Esophagus. The nerve-terminations are best studied in the oesophagus of a 

 rabbit by means of the lemon-juice and gold method. The process is described at p. 71, in 

 connection with the small intestine. 



K . 



