84 THIRD REPORT — 1833. 



more nervorum spinalium, ganglion semilunare dictum, facere 

 debet? sub quo peculiaris funiculorum fasciculus ad tevtium 

 quinti paris ramum, maxillarem inferiorem dictum, properat, 

 insalutato ganglio semilunari, ad similitudinem radicum ante- 

 riorum nervorum spinalium ?" Siimmerring has also pointed 

 out with equal clearness the resemblance in distribution be- 

 tween the smaller root of the fifth and the anterior roots of the 

 spinal nerves. But Sir Charles Bell was the first to establish 

 the identity of their functions, and to arrange them prominently 

 in the same natural division. His experiment consisted in 

 exposing the fifth pair at its root, in an ass, the moment the 

 animal was killed. " On irritating the nerve, the muscles of the 

 jaw acted, and the jaw was closed with a snap. On dividing 

 the root of the nerve in a living animal, the jaw fell relaxed." 

 In another experiment the superior maxillary branch of the 

 fifth nerve was exposed. " Touching this nerve gave acute 



pain ; the side of the lip was observed to hang low, and 



it was dragged to the other side." Sir Charles Bell concluded 

 that the fifth nerve and its branches are endowed with the attri- 

 butes of motion and sensation. This, though correct as regards 

 the nerve itself, viewed as a whole, is strictly true only of the 

 lowest of its three divisions, viz. the inferior maxillary. The 

 ophthalmic and the superior maxillary, the subject of the last 

 experiment, are nerves simply of sensation. Mr. Herbert Mayo 

 in the Essay already referred to, has pointed out this error, 

 and has defined with minute precision the relative offices of the 

 fifth and seventh nerves. By a careful dissection of the fifth 

 nerve he found that the anterior branch, or smaller root, which 

 goes, as Prochaska was aware, entirely to the inferior maxillary, 

 is distributed exclusively to the circumflexus palati, the ptery- 

 goids, and temporal and masseter muscles. He observed that sec- 

 tion of the supra and infra orbitar branches, and of the inferior 

 maxillary, near the foramina, whence they emerge, induces loss 

 of sensation in the corresponding parts of the face. It may then 

 be regarded as fully proved that the trigeminus or fifth pair is 

 the nerve which bestows sensation on the face and its appen- 

 dages, and motion only on the muscles connected with the lower 

 jaw. The other muscles of the face derive their motive power 

 from the portio dura of the seventh nerve. 



M. Magendie has also published several memoirs on the 

 functions of the fifth pair. In these he attempts to prove 

 that the olfactory nerve is not the nerve of smell ; that the op- 

 tic is but partially the nerve of vision ; and that the auditory is 

 not the principal nerve of hearing. It is in the fifth pair that 

 he supposes all these distinct and special endowments to reside. 



