822 THE NERVES. 



D. The Sympathetic Ganglia annexed to the Fifth Pair. — These 

 ganglia, joined by filaments of communication to the anterior extremity of the 

 gTeat sympathetic nerve, in reality belong to the special system formed by that 

 nerve-chain, as they possess the structure and properties of the other ganglia 

 composing it. It is therefore necessary that we should have a motive sufficiently 

 powerful to induce us to move them from their natural category, and mix up 

 their description with a nerve so different to them in its nature and functions. 

 This motive we find in the intimate relations of contiguity and continuity which 

 these ganglia manifest towards the branches of the trigeminus ; in the fact that 

 we sometimes find them united to these branches, and deeply mixed up with their 

 fibres; and also because, in certain cases, they seem to disappear entirely, and 

 then their filaments of emission or reception are directly received or emitted by 

 the fifth pair. 



The study we are about to undertake of each of the ganglia, will fully justify 

 what we have advanced. We will precede it by a few words of introduction, as 

 to the general facts relating to these small organs. 



The number of sympathetic ganglia annexed to the fifth pair is susceptible of 

 variation, not only in different species, but also with individuals of the same species. 



In the domesticated Mammifei-s, we somewhat constantly — though not 

 invariably — find three principal ganglia placed on the course of the branches 

 emanating from the Gasserian ganglion. These are : 1. The ophthalmic ganglion, 

 belonging to the nerve of the same name. 2. The spJieno-palatine ganglion, 

 annexed to the superior maxillary branch. 3. The otic ganglion, wliich lies 

 beside the inferior maxillary nerve. Anatomists describe other two — the sub- 

 maxillarg ganglion and the naso-palatine (or Cloquefs) ganglion ; but we have 

 not yet dissected them in Solipeds, though they should exist. The submaxillary 

 ganglion has been found in the Dog at a short distance from the point where the 

 lingual nerve gives off a branch to the maxillary gland. It receives sensitive 

 roots from the lingual, and motor roots (vaso-motor or excito-glandular) from 

 the chorda tympani. 



These small bodies possess those common characters which have been so 

 clearly indicated by Longet, and to which we will briefly refer. All are in 

 communication with the superior cervical ganglion by one or more generally very 

 slender filaments, and all receive one or more ramuscules from a sensitive and 

 a motor nerve ; these ramuscules — the afferent branches of the ganglia — are 

 considered as their roots. All, finally, emit from their periphery a more or less 

 considerable number of emergent branches or ramifications, which share the 

 properties, more or less modified, of the two orders of roots. The description of 

 each ganglion therefore includes, independently of its form, situation, etc., an 

 indication of all these ramuscules — ramuscules of communication with the superior 

 cervical ganglion ; afferent ramuscules or roots ,• and emergent ramuscules. This 

 rule can be applied to all the ganglia, and renders their study perfectly methodical. 



1. Ophthalmic (Ciliary or Lenticular) Ganglion. — This ganglion is 

 readily discovered, as it is always in contact with the common oculo-motor nerve, 

 and united to it near the point where the branch passing to the inferior oblique 

 muscle arises. It rarely exceeds the volume of a grain of millet, and is sometimes 

 so minute that it would altogether escape observation, did we not know exactly 

 where to look for it. 



Its motor joot is generally formed of two veiy short ramuscules coming from 

 the third pair. Its sensitive root, much longer, proceeds from the palpebro-nasal 



