GENERAL PROPERTIES OF THE GLOSSO-PHARYNGEAL 641 



the spheno-palatine ganglion. In addition to these, a branch has been 

 described as going to the geniculate ganglion of the intermediary nerve 

 of Wrisberg. 



A little below the posterior foramen lacerum, the glosso-pharyngeal 

 sends branches to the posterior belly of the digastric and to the stylo- 

 hyoid muscle. There is also a branch which joins a filament from the 

 facial to the stylo-glossus. 



Opposite the middle constrictor of the pharynx, three or four branches 

 join branches from the pneumogastric and the sympathetic, to form 

 together the pharyngeal plexus. This plexus contains a number of 

 ganglionic points, and filaments of distribution from the three nervps 

 go to the mucous membrane and to the constrictors of the pharynx. 

 The mucous membrane probably is supplied by the glosso-pharyngeal. 

 It is probable, also, that the muscles of the pharynx are supplied by fila- 

 ments from the pneumogastric, which are derived originally from the 

 spinal accessory. 



Near the base of the tongue, branches are sent to the mucous mem- 

 brane covering the tonsils and the soft palate. 



The lingual branches penetrate the tongue about midway between 

 its border and centre, are distributed to the mucous membrane at its 

 base and are connected with certain of the papillae. 



General Properties of the Glosso-Pharyngeal. To ascertain the gen- 

 eral properties of this nerve, it must be stimulated at its root before it 

 has contracted anastomoses with other nerves ; and the nerve must be 

 divided in order to avoid reflex phenomena. Taking these precautions it 

 has been found that stimulation of the peripheral end of the nerve does 

 not give rise to muscular movements. There can be no doubt of the fact 

 that the nerve is sensory, although its sensibility is dull. In experi- 

 ments in which the nerve has seemed to be insensible to ordinary im- 

 pressions, it is probable that the animals operated on had been exhausted 

 more or less by pain and loss of blood in the operation of exposing the 

 nerve, which, it is well known, abolish the sensibility of some of the 

 nerves. 



Experiments on the glosso-pharyngeal are not very definite and sat- 

 isfactory in their results as regards the general sensibility of the base of 

 the tongue, the palate and the pharynx. The sensibility of these parts 

 seems to depend chiefly on branches of the fifth, passing to the mucous 

 membrane through Meckel's ganglion. Experiments show, also, that the 

 reflex phenomena of deglutition take place mainly through these branches 

 of the fifth, and that the glosso-pharyngeal has little or nothing to do 

 with the process. In fact, after division of both glosso-pharyngeal 

 nerves, deglutition does not seem to be affected. Stimulation of the 



