FUNCTIONS OF MOTOR AND SENSORY NERVES 101 



mine is apparent on the face of it; by respiratory nerves, 

 he meant, as he himself describes, those nerves which are 

 dependent on or related to the act of respiration. The 

 muscles in question included those of deglutition, of phonation, 

 of smelling, etc., as well as the more purely respiratory 

 muscles." 



Bell's third and fourth papers to the Royal Society (1823) 

 deal with the muscles and nerves of the eyeball and orbit but 

 from our present historical standpoint they are of significance 

 only on account of the allusions they contain to the physiology 

 of the fifth nerve and to Magendie's work of 1822. The first 

 part of this double paper (March 20) deals principally with the 

 motions of the eye and hardly concerns us ; it contains no 

 allusion to motor and sensory functions of nerve nor to the 

 fifth nerve nor to Magendie. 



The second part (June 19) begins with an account of the 

 function of the ophthalmic division of the fifth nerve, which it 

 describes as being that by which — 



" the common endowment of sensibility is bestowed upon the 

 membranes and surfaces of the eye." Bell now says that the 

 "trigeminus or fifth nerve bestows upon all the surfaces of 

 the head and face, external and internal, that sensibility which 

 is enjoyed by the rest of the body through the spinal nerves." 

 He says that "it has been shown in a preceding paper, by 

 experiment, that on dividing the branch of the fifth nerve 

 to the cheek and lips the skin was deprived of sensibility 

 although in possession of other nerves and enjoying muscle 

 activity." 



We have to remember that Bell is now writing in 1823, i.e. 

 after Magendie of 1822; his statement that he knew all this 

 about the fifth nerve in 1821 is not borne out by reference to 

 the paper of 182 1, when he imagined that the fifth nerve was 

 motor-and-sensory. And now we understand the alterations 

 alluded to above in the passage about the fifth nerve as 

 republished in 1824. 



The next section in this paper on the eye deals further with 

 nerves performing the involuntary motions, which he associated 

 with the respiratory nerve of the face; it ends up with a 

 footnote containing an indirect claim to having demonstrated 

 distinct functions in the separate roots of the spinal nerves 

 (p. 294). The next section deals with the fourth nerve, which 



