288 DIGESTIVE ORGANS. [sect. 136. 



with concentrated caustic potash, which detaches the epithelium. The papillae 

 of the tongue, whose epithelium, especially in the filxformes, is frequently 

 not found entire, are to be treated exactly in the same manner. The nerves 

 of all these parts are best seen on the addition of diluted caustic soda ; acetic 

 acid also frequently serves for this purpose. The muscles of the tongue 

 are to be investigated by minute dissection, and the arrangement of fibres 

 may be tolerably well made out by this means in half macerated tongues, 

 which have lain for a long time in alcohol. Fresh tongues may also, be 

 employed, but they are not nearly so weU fitted for the purpose, and it 

 is generally necessary to boil them until they are quite soft. In order to 

 obtain sections for the microscope, the tongue may be dried or hardened 

 in alcohol, or hard boiled. In all these three cases caustic soda is useful for 

 giving clearness, although it somewhat attacks the muscular fibres. Perpen- 

 dicular, longitudinal, and transverse sections in various directions, are to be 

 recommended, especially through the glandular region. Concerning the in- 

 vestigation of the glands, we have already mentioned what is most important. 



Literature. — W. Bowman, Art. Mucous Membrane, in Todd's Cyclopaedia of 

 Anatomy, Apr. 1842. E. H. Weber, in Meckel's Archiv., 1827, pp.276, 280. 

 A. Sebastian, Becherches Anatomiqucs, Physiologiques, et Pathologiqv.es sur 

 les Glandes Labiates, Groningen, 1842. N.Ward, Art. Salivary Glands, in 

 Todd's Cyclopeedia of Anatomy, Sept. 1848, partxxxiii., p. 421. Donders, in 

 Ned. Lane, 1853, Oct. Nov., p. 295. Bernard, in Mem. de la Soc. d. Biol. 

 C. J. Baur, in Meckel's ArcJiiv., 1822, p. 350. P. F. Gerdy, Becherches 

 d Anatomic, de Physiologic et de Pathologie, Paris, 1823. P. T. Blandin, in 

 Archiv. Gener. de Medicine, 1823. J. Zaglas, in Annals of Anatomy and 

 Physiology, ed. by J. Goodsir, 1850, i. p. 1. H. Hyde Salter, Art. Tongue, in 

 Todd's Cyclopaedia of Anatomy, iv., June and Sept., 1850. C. B. Bruhl, 

 Kleine Bcitrdge zur Anatomic der Haussdugethiere, Wien, 1850, pp. 1-6. 

 Sappey, Compt. rend., 1847, p. 26. The reader, may also consult the anato- 

 mical works of E. H. Weber, Valentin (iriv Haridw. d. Phys.), Todd and 

 Bowman, Henle, Arnold, Hdschke, Krause, and myself ; and the drawings 

 of Berres, Arnold, Langenbeck, Ecker, Beau and Bonamy. ' 



Of the Teeth. 



§ 136. The teeth (denies) are hard organs implanted in the 

 alveolar processes of the jaws, which, although in some points quite 

 the same in structure as the bones, in others closely related to 

 them, yet must, in respect of their development, be regarded as 

 pertaining to the mucous membrane. 



In every tooth we distinguish the proper tooth and the soft 

 structures. The former is divided into a free part, the crown 

 (corona), and an imbedded portion, the simple or divided fang or 

 root (radix), whose various forms will be found described in the 

 text-books of anatomy. In its interior is a small cavity, the cavity 

 of the tooth (cavum dentis), pulp-cavity, which, prolonged in form 



