A. ORAL CAVITY, BY E. KLEIN. 501 



through the mucous membrane. The plexiform tissue com- 

 posed of fasciculi of fine connective tissue fibres belonging to 

 the submucous layer, and which, together with delicate fre- 

 quently coiled elastic fibres, forms the framework of the gland, 

 is at the same time the support of small nerves, and of a close 

 system of capillaries which surround the acini. 



In this tissue there lie, partly isolated amongst the fine fibres 

 of the connective tissue fasciculi, partly accumulated in larger 

 numbers near and around the acini, lymph corpuscle-like cells, 

 as well as large, coarsely granular, irregularly shaped masses 

 of protoplasm, which usually contain a small nucleus. 



Sebastian* counted fifty-seven glands in the lower lip alone ; 

 in other cases there were thirteen and twenty-one of these 

 glands. Their diameter amounts from J to 1^ millimeter, or 

 more ; and as a rule their size increases in proportion to th e 

 smallness of their numbers ; they are largest in children, and 

 diminish as age advances, 



In the lower lip of the childf they are arranged in four or 

 five consecutive rows. Their number rarely exceeds three 

 in the upper lip, and they are altogether absent at the 

 angles of the mouth. J I find that in the child they are larger 

 in the lower than in the upper lip. Besides the glands, large 

 vessels and nerves are also found in the submucous tissue of 

 the muco-membranous portion, the latter for the most part 

 running in a vertical direction, giving off smaller branches to 

 the mucous membrane, which again subdivide, and may be 

 followed to the immediate vicinity of the epithelium. 



The nerves of the papillae have not been accurately investigated. 

 According to W. Krause, the so-called terminal bulbs structures 

 respecting the nature of which there is still some doubt are found 

 in the lips of many Mammals. 



KollikerJI has observed in the papillae of the lips, but only of that 

 part which is visible when the mouth is closed, tactile corpuscles, and 



* Sebastian, Recherches anatomiques, physiologiques, pathologiques, et 

 semeiologiques sur les Glands Labiales. Groningen und Bremen, 1842, 4to. 

 t E. Klein, loc. cit. 

 J Henle, Splanchnologie, p. 138 



W. Krause, Die terminalen Korperchen. Hanover, 1860. 

 i| Zeitschrift fiir wissenschaftliche Zoologie, Band iv., Heft i. p. 43. 





