SiGERSON — On the Study of Nerve Action. 267 



external agents, amongst which we may enumerate parasites. This 

 statement may be illustrated by the facts of another case, which was 

 noted down in 1864, and was made the subject of a Paper by the late 

 Professor Gubler. In this case, the symptoms of which, unfortu- 

 nately, were not given with much minuteness, we find the existence 

 of anaesthesia of the trigeminus mentioned, as supervening upon 

 another disorder. Sensibility, consequently, was impaired over the 

 left side of the face. The patient having complained of dryness of 

 the mouth, and disagreeable sensations there, attention was directed 

 to the state of the buccal cavity. On examination it was ascertained 

 that the gums and inner side of the cheek on the left side were dis- 

 tinctly drier than the corresponding parts on the right. In addition, 

 a very striking phenomenon was observed. On the left, that is, the 

 anaesthetic side, white granular patches were found disseminated over 

 the posterior gums, the genial mucous membrane, and the angle of 

 the upper and lower maxillee. Nothing of the kind was to be dis- 

 covered on the right side. On microscopic examination of scrapings 

 of the white patches, epithelial cells, spores, and numerous long fila- 

 ments of O'idium albicans were found.® 



This case supplies an interesting and instructive corroboration 

 of certain conclusions drawn from the facts which came under my 

 personal observation, and gives us some additional data for judging 

 the mechanical cleansing theory. Here were two regions perfectly 

 identical as regards their motor conditions, as well as with respect 

 to whatever friction they might experience. From one region, how- 

 ever, the influence of the trigeminus was more or less completely 

 withdrawn, owing to its paralysis, and, in this region, parasitical 

 growths were found to develop on the surface membrane, whilst no 

 such phenomena were discoverable in the region where trigeminal 

 action remained intact. 



Prom what precedes, it is necessary to conclude : — 



1°. That the action of the trigeminus influences, in a marked 

 manner, the nutrition of the epithelial cells of the tongue and other 

 parts to which its filaments are distributed. 



2°. That diminution of its action is followed by diminution of the 

 ' desquamation process. 



3°. That, owing to this arrest of elimination of effete cells, the 

 senses of Touch and Taste become impaired. 



4°. Diminished action of the trigeminus results in diminished 

 power of resistance, on the part of the corresponding surface mem- 

 brane, to the action of pathological alteration in its anatomical elements 

 and to the invasion of external agents, such as parasitical growths. 



® Professor Gubler' s attention having been confined to the phenomenon of dry- 

 ness, he failed to discern the real cause at work. He, in fact, candidly records his 

 failure. 



