570 THE NERVOUS SYSTEM. 



their ganglia, as the cardiac, the solar, the renal and hypo- 

 gastric plexuses ; and in the same division may be included 

 the ganglia in the neighbourhood of the head and neck, 

 namely, the ophthalmic or lenticular, the spheno-palatine, 

 the otic, and the submaxillary ganglia (fig. 152). 



The structure of all these ganglia appears to be essen- 

 tially similar, all containing 1st, nerve-fibres traversing 

 them; 2ndly, nerve-fibres originating in them; r $rdly, 

 nerve- or ganglion-corpuscles, giving origin to these fibres; 

 and 4thbj, other corpuscles that appear free. And in the 

 trunk, and thence proceeding branches of the sympathetic, 

 there appear to be always 1st, fibres which arise in its 

 own ganglia; 2ndly, fibres derived from the ganglia of 

 the cerebral and spinal nerves ; ^rdly, fibres derived from 

 the brain and spinal cord and transmitted through the 

 roots of their nerves. The spinal cord, indeed, appears 

 to furnish a large source of the fibres of the sympathetic 

 nerve. 



Respecting the course of the filaments belonging to the 

 sympathetic, the following appears to have been deter- 

 mined. Of the filaments derived from the ganglia on the 

 cerebral nerves, some may pass towards the brain ; for, in 

 the trunks of the nerves, between the ganglia and the 

 brain, fine filaments like those of the sympathetic are 

 found. But these may be proceeding from the brain to 

 the ganglia ; and, on the whole, it is probable that nearly 

 all the filaments originating in the ganglia or cerebral 

 nerves, go out towards the tissues and organs to be sup- 

 plied, some of them being centrifugal, some centripetal; 

 so that each ganglion with its outgoing filaments may form 

 a kind of special nervous system appropriated to the part 

 in which its filaments are placed. Such, for example, may 

 be the ophthalmic ganglion with the ciliary nerves, con- 

 nected with the brain and the rest of the \ sympathetic 

 system by the branches of the third, fifth, and sympa- 

 thetic nerves that form its roots, yet, by filaments of its 



