416 FUNCTIONS OF NERVES. 



straight muscles of the eyes, the inferior oblique, and the levator 

 palpebrae superioris, the superior oblique, the abductor straight 

 muscle, many muscles of the face, viz. the orbicularis, levator 

 anguli oris, &c. &c. or the muscular fibres of the tongue. If 

 the spinal chord, or nerves conveying both volition from the 

 brain and impressions to the brain, the supplied parts lose both 

 sense and motion. f For when nerves both convey volition and 

 supply common sensibility, as the fifth and the spinal nerves, they 

 are compound, one portion performing but one function, as is 

 proved by separately dividing the anterior and posterior part 

 of the trigeminum, or the nervous bands, proceeding from the 

 anterior and posterior parts of the spinal chord, before their 

 conjunction; when the division of the former deprives the parts 

 supplied of the influence of volition, and that of the latter de- 

 prives them of sensation. In the case of either these com- 

 pound or the simply motor nerves, if the divided surface, now un- 

 connected with the brain, is irritated (or if, indeed, the parts 

 are not divided, but at once irritated by pinching), contractions 

 occur in the muscles supplied by them ; and, if a sedative is 

 applied to them, some say that the muscles become inert. In 

 the case of the compound nerves too, and in the case also of the 

 division of those nerves which have common sensibility or touch 

 and constitute a part of compound nerves, if the divided sur- 

 face connected with the brain is irritated, acute pain is felt, 

 as if in the part on which the nerve originally terminated s 

 and, after the removal of a limb, it is common for uneasy sens- 

 ations to be experienced by the patient as if he still possessed 

 his hand or his foot. The nerves which convey volition only, and 



f These facts are too frequently proved to be doubted ; and, consequently, 

 four cases, in which the spinal chord is said to have been divided without the 

 effect of paralysis, must be suspected of error. (See Metzer's Principes de Me- 

 decine legate, translated, with notes, by Ballard, p. 357. sq.) Another has been 

 quoted from Dr. Magendic's Journal de Physiologic, t. iii., in which the arms 

 were paralysed as to motion, and the lower cervical and upper dorsal chord was 

 a colourless pulp, except two bands between the anterior fissure and the sides ; 

 so that the anterior portion of the chord was continuous (p. 184.), though 

 the posterior was destroyed at one part. But the description is imperfect. Dr. 

 Magendie suggests that the membranes carried on sensation ! 



g Thus, after the loss of the glans penis, the extremities of the nerves are sens- 

 ible to venereal pleasure, as noticed by John Hunter and Dr. Marshall ; and I 

 once had an out-patient at St. Thomas's Hospital with gonorrhrea, and only an 

 inch of a remnant of penis. 



