38 SPECIAL HISTOLOGY. 



aperture (Sebastian, in ' Van Setten, Diss, de Saliva/ 1837, 

 p. 12). 



The best mode of examining the oral mucous membrane is 

 by making perpendicular sections of portions, either fresh, or 

 dried, or hardened in absolute alcohol, in which the papillae and 

 epithelium are very distinct, and become still more so by the 

 use of very dilute caustic soda ; by the aid of which also the 

 deepest perpendicular epithelial cells are rendered readily visible. 

 The papillae may be studied in macerated portions, or if it be only 

 required to ascertain their position and form, in perpendicular 

 or horizontal sections, treated with concentrated caustic potass, 

 on which the epithelium is dissolved. The lingual papillae may 

 be treated in the same manner; the epithelium upon which, 

 especially on the filiformes, moreover, is often entirely absent. 

 The nerves of all these parts are best seen under the use of 

 dilute caustic soda; acetic acid is also frequently of service. 

 The muscular substance of the tongue must be examined by 

 minute dissection, a method which may be carried very far, espe- 

 cially in tongues which are half macerated from having long lain 

 in spirit. Recent tongues are also of use, but are by no means 

 so good, and it is usually necessary to boil them until they are 

 quite soft; and to procure sections for the microscope the 

 tongue may be dried or hardened by boiling, or by strong 

 alcohol. In all three methods caustic soda is of great service 

 in clearing up the tissue, although it undoubtedly attacks 

 the muscular fibres a little. Perpendicular and longitudinal 

 sections in various directions are to be recommended, especially 

 in the glandular region. With respect to the glands, the most 

 important points have been already stated.] 



Literature. — W. Bowman, Art. ' Mucous Membrane/ in 

 Todd's ' Cyclopaedia of Anatomy/ April, 1842 ; E. H. Weber, 

 * Ueber die Schleimbalge und zusammengesetzten Driisen der 

 Zunge und uber den Bau der Parotis/ in Meckel's ' Archiv/ 

 1827, pp. 276-280; A. Sebastian, ' Recherches anatomiques, 

 physiologiques et pathologiques sur les glandes labiales/ Gro- 

 ningue, 1842 ; Nuhn, s Ueber eine bis jetzt nicht naher be- 

 schriebene Druse im Innern der Zungenspitze/ Mannheim, 1845; 

 N. Ward, Art. ' Salivary Glands/ in Todd's ' Cyc. of Anat./ 

 Sept. 1848, part xxxiii, p. 421 ; C. Rahn, c Einiges iiber die 

 Speichelsecretion/ Zurich, 1850; C. Ludwig, f Neue Versuche 





