GANGLION. 



375 



b. What is the nature of the fibres which 

 are connected with the ganglia? The very 

 interesting inquiries of Brown, Danvall, Teale, 

 Stanley, and others into the nature of those 

 frequent affections now generally known under 

 the term of neuralgic diseases, by which a 

 new and unexpected light lias been thrown 

 on a most obscure branch of pathology, 

 render this part of the present investigation 

 of pre-eminent importance. The mutual in- 

 fluence exerted by the cerebro-spinal axis 

 and the great sympathetic on each other, 

 in consequence of which disease of the brain 

 and spinal chord may cause morbid actions 

 and conditions of the organs of digestion, 

 circulation, and secretion, and vice versa, can 

 only be experienced by a reference to the 

 relations which exist between these two great 

 divisions of the nervous system. Unfortu- 

 nately, however, this question, so important 

 both as regards physiology and pathology, is 

 not easily resolved on account of the difficulty 

 in the present state of our knowledge of dis- 

 tinguishing from each other the different species 

 of fibres which enter into these organs. I 

 shall in the first place speak of the fibres 

 which are perceptible to the naked eye, and 

 afterwards point out the information that has 

 been afforded by microscopical examination. 



The intervertebral ganglia (and these ob- 

 servations may be applied to those of the 

 fifth pair, of the glosso-pharyngeal, and of 

 .the pneumo-gastric) receive fibres only from 

 the posterior roots of the spinal nerves, "which, 

 since the researches of Bell, Magendie, and 

 Mayo, have been regarded as being subordinate 

 to sensation. But if the important principles 

 announced by Dr. M. Hall be susceptible, as 

 I believe they are, of that confirmation from 

 anatomical examination of which at present 

 .they stand in need, then to the true sensiferous 

 fibrils which enter these ganglia we must add 

 what are called by Dr. Hall incident filaments. 

 It is also a question which yet remains to 

 be decided, whether the twigs that are known 

 to run between the posterior roots of the spinal 

 nerves and the sympathetic ganglions pass in 

 reality from the former to the latter or from 

 the latter to the former; if, as appears most 

 probable, these threads are furnished by the 

 sympathetic, then it is to be presumed they 

 are subsequently continued to the intervertebral 

 ganglions. 



With respect to the sympathetic ganglions, 

 the following are the only facts that are at this 

 time established, 



1. There are longitudinal commissural fila- 

 ments by which the ganglia are joined to each 

 other, and by which they are formed, however 

 remote they may be from one another, into 

 one great and extensive system. 



2. There are fibrils which extend between 

 the motiferous part of the cerebro-spinal axis 

 and the sympathetic, but whether they are 

 derived from the former or the latter is not de- 

 cided. 



3. There are sentient fibrils observing a 

 similar disposition. 



As the anatomical facts by which these facts 



are established will be found under the head 

 SYMPATHETIC NERVE, only a few remarks are 

 required in this place. 



1. With respect to the longitudinal com- 

 missural fibres, they are as necessary here as 

 in other parts of the nervous system ; and 

 although Bichat speaks of this connexion of 

 the ganglions being occasionally absent, such 

 deficiencies are extremely rare, and if they 

 do really exist, must be regarded as an ab- 

 normal state. The importance of this con- 

 nexion is rendered apparent by the union of 

 the several nodules placed on the trunk of the 

 sympathetic, which is so constant that anato- 

 mists were for a long time so far misled by 

 it as to compare this gangliated cord with the 

 common nerves of the body ; but it is perhaps 

 still more striking in the commissural fibres, 

 which are so invariably noticed passing from 

 the sympathetic to the small ganglia of the 

 head. 



2 and 3. In consequence of the motor and 

 sentient nerves of the head usually forming 

 distinct trunks, the ophthalmic ganglion offers 

 a natural analysis, as it were, of the connexion 

 between the great sympathetic and the cerebro- 

 spinal axis. One twig passes between this 

 small body and the nasal nerve of the fifth pair 

 (sentient); a second extends between it and 

 the lower division of the third pair (motor). 

 The dissections of Arnold prove that a similar 

 connexion exists in the spheno-palatine, the 

 otic, and the submaxillary ganglia.* Mayo 

 has also ascertained that the branches placed 

 between the ganglia of the great sympathetic 

 and the compound nerves of the spine are 

 of a twofold character, one set being attached 

 to the sentient and the other to the motor root. 

 The adjoining figure (fig. 172), copied from a 

 dissection I made for this purpose, shows the 

 mode of communication in the thorax. 



Fig. 172. 



a, Anterior root. c, Ditto. b, Posterior root 

 entering the ganglion, d, Sympathetic ganglion. 



e, Filament of communication to posterior root. 



f, Filament of communication to anterior root. 



* These connexions are very beautifully repre- 

 sented in his work, Icones Nerv. Capit. Tab. 5, 6, 

 7, and 8. On some points relative to the otic 

 ganglion it has been proved by the dissections of 

 Schlemm that Arnold was in error, especially as 

 relates to the branch supposed to be furnished from 

 the ganglion to the tarsor tympani. 



