FIFTH PAIR OF NERVES. 



313 



them ; for by destroying the sensation of the 

 organ, it must leave it exposed to the unin- 

 terrupted influence of many irritating agents, 

 which naturally would excite inflammation, 

 were it not that we are warned through the 

 sensibility of the organ to avoid or to remove 

 them, but in every such case they are the im- 

 mediate, and the insensibility only the mediate 

 cause of the effects produced, and such, it ap- 

 pears to the author, is the part played by the 

 section of the fifth in giving rise to inflamma- 

 tion in the eye. It is further to be observed 

 that the occurrence of inflammation in the 

 eye in cases in which the influence of the fifth 

 nerve upon it had been lost, had been noticed 

 and given to the public by Bell prior to the 

 publication of it by Magendie. In the Philo- 

 sophical Transactions for 1823, (Magendie's 

 memoir dates 1824,) Sir C. Bell reports the 

 case of a patient under the care of his colleague 

 Dr. Macmichael, in which the surface of the 

 eye was totally insensible, and the eye re- 

 mained fixed and directed straightforward, 

 while the vision was entire. " The outward 

 apparatus being without sensibility and mo- 

 tion, and the surface not cleared of irritating 

 particles, inflammation has taken place, and 

 the cornea is becoming opaque ; thus proving 

 the necessity of the motions of the eye to the 

 preservation of the organ." And in the same 

 volume he reports also a case from the expe- 

 rience of Mr. Crampton of Dublin, bearing 

 strongly upon the question, because it shews 

 satisfactorily that the sensation of the organ, 

 and consequently the influence of the nerve, 

 may be obliterated, and inflammation not 

 ensue until a stimulus have been applied, 

 though the conjunctiva manifestly retained its 

 susceptibility to the impression of that sti- 

 mulus. Mr. Crampton's account of the case 

 is as follows: " When she told me her eye was 

 dead, as she expressed it, to be certain I drew 

 my finger over its surface, and so far was this 

 from giving her pain, that she assured me she 

 could not feel that I was touching it at all. The 

 eyelids made no effort to close, while I was 

 doing this; but the conjunctiva appeared sen- 

 sible to the stimulus, as a number of vessels on 

 the surface of the eye became immediately in- 

 jected with blood." 



Another circumstance may be advanced in fa- 

 vour of the opinion that the nerve influences the 

 nutrition of the parts, to which it is necessary to 

 allude, viz. the wasting of the muscles of masti- 

 cation in cases of the loss of the nerve's influence. 

 This fact may be otherwise explained ; the de- 

 velopment of muscles is always influenced by 

 their exercise, which being lost they waste, and 

 it is neutralized by the counter-fact that, though 

 these masticatory muscles waste, the muscles 

 of the face and its other structures do not. In 

 fine there appears to the writer to be no good 

 reason for attributing to the fifth nerve a direct 

 influence upon the nutrition of the structures 

 to which it is distributed; the existence of such 

 an influence would be incompatible with the 

 simplicity of natural laws, for in such case 

 there must be two such influences in existence, 

 one in the nerve directing the nutrition of the 



parts with which it is connected, and another 

 elsewhere to direct that of the nerve. 



Magendie confirms his view of the influence 

 exerted by the fifth nerve upon the functions 

 and nutrition of the eye, by reference to a case 

 published by Serres in the* fifth volume of the 

 Journal of Physiology, which " presented all 

 the phenomena attending section of the fifth 

 pair," and in which there existed complete 

 alteration of the trunk of the nerve in its sen- 

 sible portion ; " followed by loss of sight, of 

 smell, of hearing, and of taste on the same 

 side." Before detailing this case, the writer 

 cannot refra.n from observing that in such 

 cases none but unquestionable evidence can be 

 admitted if we would arrive at a certain and 

 unquestionable conclusion. Whether the case 

 of Serres be such, it rests with the reader to 

 decide; and first, what was the condition of 

 the patient in other respects? Serres replies : 

 " His air was dull; his physiognomy gave, at 

 first sight, the idea of imbecility; he seemed 

 to conceive slowly and to comprehend with 

 difficulty, the questions which were put to 

 him. When he wished to reply, it was evi- 

 dent that he experienced difficulty in express- 

 ing himself; he pronounced with difficulty, 

 and the little that he said seemed to require, 

 on his part, a considerable effort : his cranium 

 was voluminous compared to the rest of his 

 body; some pupils suspecting a commencing 

 hydrocephalus, thought that they observed a 

 separation between the parietal and temporal 

 bones, but the prominence of the eyes made 

 me reject that conjecture; the maxillary and 

 malar bones were a little separated, which 

 had produced a flattening of the nose ; the pa- 

 tient had some difficulty in moving the tongue; 

 the motions and sensibility of the limbs were 

 not affected, only he moved the lower extre- 

 mities less freely than the upper ; he had been 

 for some time subject to epilepsy; he had a 

 sister deaf and dumb." A case so complicated 

 as this, in which there manifestly existed ex- 

 tended disease of the encephalon, must be 

 rejected as altogether inconclusive. But to 

 proceed, the patient was admitted into hospital 

 in September 1823: at his admission he had a 

 chronic ophthalmia of his right eye, which was 

 considered scrofulous. In the course of De- 

 cember he was attacked by an acute ophthalmia 

 of the same eye, attended by adema of the lids, 

 and commencing opacity of the cornea; the 

 ophthalmia was dispersed after ten or twelve 

 -days ; but the cornea was rendered altogether 

 opaque throughout its whole extent; of course 

 the loss of vision on that side was the neces- 

 sary result. In the course of January 1824 it 

 was observed that the right eye was insensible, 

 and soon after that the eyelid and nostril of the 

 same side were also insensible, and likewise 

 the tongue on that side, while all was natural 

 on the other; soon after the gums inflamed 

 upon the right; they were red, some white 

 places existed here and there, they were swollen 

 at the circumference of the sockets ; the tongue 

 moved always with difficulty; the hearing was 

 not then affected ; in July the affection of the 

 gums extended to the left side, but the right 



