22 SPECIAL HISTOLOGY. 



possibly, to be sought for in the nerves. In the p. circumvallatce, 

 the nervous fibres are always finer, and not only absolutely, but 

 also relatively, considerably more numerous than in the fungi- 

 formes, so that they possess more papillae and nervous termina- 

 tions in the same space. The fineness of the nerves especially, 

 together with the smaller quantity of medullary sheath and the 

 more superficial position of the axis-fibre, which indeed is the 

 case in all the nerves of the higher senses, may perhaps explain 

 why tastable substances act here not only more powerfully, 

 but when they are no longer perceptible by more dense elements 

 of the nerves. If this peculiarity be insufficient to account for 

 the differences in the sense of taste possessed by the two kinds 

 of papillae, they can only be referred to the central organs, or 

 ascribed to specific actions in the nervous fibres themselves, 

 which, however, is only making a public confession of the 

 hiatus in our knowledge. 



Remak 1 discovered microscopic ganglia upon the expansion 



1 [Remak, • Ueber die Ganglien der Zunge bei Saugethieren und beim Menscben.' 

 The author finds ganglia upon the branches of the glosso-pharyngeal and of the 

 gustatory nerves, and not upon those of the ninth nerve ; small ganglia were some- 

 times observed near branches of the latter, but were never actually connected with 

 them, and probably belonged to neighbouring branches of the gustatory. Remak 

 compares these ganglia with those observed by himself in the heart, contractile wall 

 of the bronchiae, posterior wall of the urinary bladder, and muscular wall of the 

 uterus, and with the ganglia of the cavernous plexus described by Miiller ; and his 

 reasons against their connection with the nerves of sense appear to us sufficiently 

 important to be given in his own words. 



" The terminal branches of both nerves (glosso-pharyngeal and gustatory nerves) 

 form a very dense plexus before entering the papillae. Neither in this plexus, nor 

 within the papillae themselves, could ganglion-globules ever be detected. It must 

 be remembered, further, that the ganglia upon the thicker branches of the glosso- 

 pharyngeal and gustatory are always hemiganglia, that is, they do not occupy the 

 whole thickness of the nerve — a bundle of tubules, which takes no share in the 

 formation of the ganglia, passing over them. Those ganglia which lie in the neigh- 

 bourhood of the papillae have the same structure. Far more numerous are the 

 hologanglia, i. e. those in which all the nervous fibres become lost between the gan- 

 glion globules (probably pass into them), but these are found only in the finest 

 lateral branchlets. They are almost always multipolar, i. e. they are connected 

 with more than two nervous trunks, and these are very widely different from the 

 nerves which constitute the papillary plexus. While the latter present very delicate 

 sheaths, and consist of evident dark-edged fibres, the processes of the hologanglia 

 are closely surrounded and enveloped by very dense sheaths, and contain, particularly 

 in the lingual branch of the fifth, both in man and in the sheep and calf, a very 

 large quantity of the well-known nucleated fibres, so that it is at times difficult to find 



