EXAMINATION OF SOME SPINAL NERVES 55 
uvula. On the other hand, the surface of the anterior pillar of the fauces and of the tonsil are 
fully sensitive. On the palate, as on the tongue, the anaesthesia extends up to the median line, so 
that a crossed overlap of right and left fields must in this region be very slight, or may not exist. 
After section of the Vth cranial I have always failed to obtain evidence from the Monkey 
of persistence of any sense of taste. Monkeys normally react briskly to quinine or cayenne 
placed upon the tongue. After the intracranial section of the trigeminus the sensitiveness of the 
front two-thirds of the organ seems lost to these substances as well as to mechanical and thermal 
stimuli. Either the chorda tympani contains no gustatory fibres, or the gustatory fibres existing in 
it are in some way derived from the trigeminus ; this latter supposition appears on anatomical and 
Fig. I 
morphological grounds hardly possible. It is hardly possible to obtain from experiment upon 
laboratory animals any minute evidence about the sense of taste, but my experiments point clearly 
to abolition — complete removal — of the sense of taste in the anterior two-thirds of the tongue, i.e.^ 
in front of a line a few millims. anterior to the circumvallate papillae. After intracranial section 
of the Vth the sense of taste behind that line still remains intact. This indicates that the gustatory 
fibres in the glosso-pharyngeal are not traceable to the trigeminal root, and that the gustatory and 
tactile fields of the two nerves are, on the dorsum linguae, coterminous. 
The Nose. 
The crossed overlap along the bridge of the nose is distinct though slight. The nasal 
mucous membrane, as far inward as can be examined easily from the nostril, gives no response 
either to mechanical or thermal excitation after intracranial section of the trigeminus. 
