454 SPECIAL HISTOLOGY. 



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* discovered microscopic ganglia upon the expansion of the 



*[ Remak, " Ueber die Ganglien der Zunge bei Saiigethieren und beim Menschen." 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 sometimes observed near branches 

 of the latter, but were never actually connected with them, and probably belonged to neigh- 

 boring 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 pa- 

 pillae 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 tu- 

 bules, which takes no share in the formation of the ganglia, passing over them. Those 

 ganglia which lie in the neighborhood 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 ganglion 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 hohganglia 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 a single dark edged fibre in one of these nerves. In other cases, 

 the processes of the ganglia are delicate nerves (of ^^ of a line), which possess a solid 

 sheath, and a single dark-edged nervous fibre enclosed by it. The fine lateral branches of the 

 hemiganglia upon the thicker branches of the nerves present the same appearances. No 

 fibres can ever be traced from a ganglion to the papillae. Another circumstance which 

 speaks against the relation of the ganglia to those fibres of the gustatory nerve which are 

 distributed to the mucous membrane is, that I could never, in spite of every exertion, find 

 ganglia upon the terminal branches of the gustatory nerve of the apex of the tongue of the 

 sheep. I believe that a certain value may be attributed to this negative result, as I never 

 failed to find ganglia upon the other branches of the gustatory nerve, up to within about an 

 inch of the apex of the tongue." 



Remak gives, further, the following reasons for believing that the ganglia are related to 

 the mucous glands. ' 1. The lingual ganglia always occur in the neighborhood of the 

 mucous glands, or of their excretory ducts. 2. That the smaller number of mucous glands 

 in the anterior region of the tongue (in the sheep or calf), corresponds with the smaller 

 number of ganglia upon the branches of the gustatory nerve. 3. That little ganglia exist 

 upon the branches of the gustatory nerve distributed to the maxillary glands, and to the 

 duclus Whartonianus, whilst in man there is the well-known maxillary ganglion. 4. That 

 in the point of the tongue of the sheep, in which he could find no ganglia on the branches 

 of the fifth, there are no mucous glands. 5. That in the walls of the pharynx and larynx, 

 upon which he also found small ganglia on the branches of the glosso-pharyngeal and supe- 

 rior laryngeal nerves (Med. Zeit., 1840, No. 2), the mucous glands are very numerous. 6. 



