SECRETION. 



469 



power supposed to be transmitted by the par 

 vagum. 



That the nutritive operations of other parts, 

 however, are usually less vigorously and cor- 

 rectly performed when the nerves have been 

 paralysed, than when they retain their entire 

 integrity, would appear from numerous other 

 facts, of which the following are examples. A 

 case is related by Mr. Swan* in which a man's 

 wrist having been injured by a cord having 

 been very tightly drawn round it, there was 

 partial paralysis of the hand, with constantly 

 repeated ulcerations of its dorsal surface ; and 

 on amputation seven years afterwards, there 

 was found to be induration of the median 

 nerve, with adhesion of the tissues beneath 

 the annular ligament. The following case, 

 stated by Mr. Paget f on the authority of Mr. 

 Hilton, is still more remarkable. " A man 

 was at Guy's Hospital, who, in consequence of 

 a fracture at the lower end of the radius, re- 

 paired by an excessive quantity of new bone, 

 suffered compression of the median nerve. 

 He had ulceration of the thumb, and fore and 

 middle fingers, which had resisted various 

 treatment, and was cured only by so binding 

 the wrist, that the parts on the palmar aspect 

 being relaxed, the pressure on the nerve was 

 removed. So long as this was done, the ulcers 

 became and remained well ; but as soon as the 

 man was allowed to use his hand, the pressure 

 on the nerves was renewed, and the ulceration 

 of the parts supplied by it returned." 



That the reparative processes are affected, as 

 well as those of ordinary nutrition, by the loss 

 of nervous power, is a matter of familiar ob- 

 servation. A striking example to this effect 

 is mentioned by Mr. Travers.J A man was 

 rendered paraplegic by fracture of the lumbar 

 vertebrae, the same accident having also frac- 

 tured his humerus and his tibia. The former, 

 in due time, united ; the latter did not. 



This peculiar affection of the nutritive pro- 

 cesses appears rather dependent upon lesion 

 of the sensory than of the motor nerves. 

 Thus we have seen that the disorganisation 

 of the eye after section of the fifth pair, takes 

 place when only the sensory nerve of the part 

 is affected, and that no such result occurs when 

 only the motor nerves of the orbit are divided. 

 In cases of disease or injuries of the spine, it 

 has been noticed that sloughing of the blad- 

 der or other parts has occurred earlier and 

 more extensively when sensation, than when 

 motion alone, has been lost. And Mr. Cur- 

 ling has noticed that two men having been 

 taken at nearly the same time to the London 

 Hospital with injury of the spine, one of 

 whom had lost only the power of motion in 

 the lower extremities, whilst the other had 

 lost both motion and sensation, at the end of 

 four months the atrophy of the lower extre- 

 mities had advanced much further in the latter 

 case than in the former. These phenomena 



* On Diseases and Injuries of the Nerves, p. 60. 

 t Loc. cit. 



j Further Inquiry concerning Constitutional Ir- 

 ritation, p. 436. 

 Med. Chirurg. Trans, vol. xx. p. 342. 



would seem to harmonise with the view, that 

 it is especially through the sympathetic system 

 of fibres that the peculiar influence is exerted, 

 whose continual agency we only recognise by 

 the results of its withdrawal. For if, as 

 already remarked, the fifth pair may be con- 

 sidered as the sympathetic of the head, the 

 Gasserian ganglion may probably be regarded 

 as belonging to the sympathetic* system ; and 

 it has been observed by Magendie, and con- 

 firmed by Longet, that the destructive inflam- 

 mation of the eye ensues more quickly after 

 division of the trigeminal nerve in front of the 

 Gasserian ganglion, than when the division is 

 made between that ganglion and the brain. 

 If this be true of the Gasserian ganglion, it 

 is probably true, also, of the ganglia on the 

 posterior roots of the spinal nerves ; and thus 

 the disordered nutrition which results from in- 

 jury to the trunks of these nerves, and which 

 is not to be accounted for by the mere disuse 

 of parts, may be attributed, with some show of 

 probability, to the interruption of the connec- 

 tion with the sympathetic system, which is 

 specially established by these ganglia and 

 their communicating cords. But it is to be 

 remembered, on the other hand, that defec- 

 tive or disordered nutrition is a marked result 

 of injuries of the spinal cord, whilst the sym- 

 pathetic centres remain uninjured ; and that 

 general atrophy is a frequent consequence of 

 chronic diseases of the brain. Fresh evi- 

 dence is much required, therefore, to deter- 

 mine the relative shares of the cerebro-spinal 

 and sympathetic centres, in regard to the in- 

 fluence exerted by them over the organic 

 functions. 



By the survey we have now taken, we are 

 in some degree prepared to estimate the 

 degree and nature of the influence exerted by 

 the nervous system on the nutritive and se- 

 cretory functions, and to inquire into the 

 validity of the several doctrines which have 

 been propounded on the subject : 



1. The first of these theories may be stated 

 in the words of Dr. Wilson Philip, one of its 

 most distinguished advocates : " It appears," 

 he says, " that the nervous influence is neces- 

 sary to the function of secretion. It either 

 bestows on the vessels the power of decom- 

 posing and recornbining the elementary parts 

 of the blood, or effects those changes by its 

 direct operation on this fluid. From many 

 facts stated or referred to in my inquiry, it 

 appears that the vessels possess no powers 

 but the muscular and elastic ; and that the 

 former, as well as the latter, is independent of 

 the nervous system . Nor is it possible to con- 

 ceive any modification of these powers by 

 which they could become chemical agents, 

 and thus be enabled to separate and recom- 

 bine the elementary parts of the blood. The 

 first of the above positions may, therefore, be 

 regarded as set aside, and the necessary infer- 

 ence seems to be, that in the functions of 

 secretion the vessels only convey the fluids 

 to be operated on by the nervous influence." 

 It will, perhaps, be sufficient to say of this 

 hypothesis, that having been put forth at a 



H H 3 



