2. Find the white ridge formed on the cheek by the parotid duct ([p. 223]). It is opposite the molar tooth, and at its cranial end the opening of the duct is seen. Enlarge the opening and insert a black bristle as far as possible.
3. Remove the skin and the skin-muscles from the side of the face, beginning at the caudal end and working craniad. At the cranial border of the carotid on the ventral side look carefully for the parotid duct with the bristle in it. The duct is then easily traced by the removal of the skin and muscles. Study the parotid gland ([Fig. 131], 10, [p. 322]).
4. Remove the facial vein ([Fig. 131], b and c) and lymphatic gland ([Fig. 131], 12) covering the submaxillary gland ([Fig. 131], 11) and clean its outer surface. Raise it and find the submaxillary duct leaving its inner surface. Reflect the digastric and mylohyoid muscles and trace the duct to the oral mucosa. The remainder of its course is shown by the bristle on the inside of the mouth.
5. The sublingual gland is uncovered in dissecting the submaxillary. Its duct is seen by the side of the submaxillary. It may be pricked near the gland and a bristle passed to its opening.
6. The infraorbital gland. Expose it by removal of the zygomatic arch and masseter muscle. Find its duct by dissecting apart the lobules at its ventral end. Prick the duct and insert a bristle to find its inner opening.
7. The molar gland. Find it by raising the orbicularis oris of the lower lip. By raising its ventral border and dissecting between it and the mucosa the ducts may be found and perhaps pricked and bristles inserted.
II. The mouth-cavity. Study the general description ([p. 221]); the lips and the cheek. Then remove the masseter muscle and the caudal part of the zygoma. Cut through the mandible between the first premolar and the canine tooth. Then disarticulate the mandible, cut the cheek and also the mylohyoid muscle and oral mucosa parallel to the medial border of the mandible, and remove the mandible with the parts thus left attached to it. The organs in the mouth-cavity are thus left exposed and should be studied. To demonstrate the incisive ducts ([p. 222]) pass a bristle into them.
The teeth ([p. 224]). These should be studied on a skull in which the roots of the teeth have been laid bare by means of the bone-forceps, as in [Figs. 93] and [94].
The tongue ([p. 226], and [Fig. 95]). Study its dorsal surface, the papillæ, etc. Then dissect its muscles ([p. 228]) from the ventral side. The stylohyoid, digastric, and mylohyoid muscles must be removed. Then dissect (a) the styloglossus ([Fig. 96], e), (b) the genioglossus ([Fig. 96], f), (c) the hyoglossus ([Fig. 96], h). Make a transverse section of the tongue to see the intrinsic muscle-fibres.
III. The thyroid gland ([p. 254], and [Fig. 96], 6). Clean the sternomastoid muscles. Cut their interdigitating portions along the median line and reflect them. Find the lateral lobe of the thyroid gland beneath the lateral borders of the sternohyoid muscles. Dissect it, being careful not to destroy the delicate isthmus.