138 MR. F. J. COLE ON THE STRUCTURE AND MORPHOLOGY OF 



remarks, p. 61 : '' 'llie ganglia of the main sympathetic chain must, according to Onodi,. 

 be considered as offshoots (Abkommlinge) of the posterior root gangh'a. If this is so, we 

 may conceive tliat the posterior root ganglion in the thoracic region may be dovible, part 

 belonging to the somatic, part to the splanchnic root. Remak described the origin of 

 nou-meduUated fibres from the posterior root ganglion as well as from the sympathetic 

 ganglia .... The connection of the fibres of the ramus visceralis with the cells of the 

 ganglion on the posterior roots of the thoracic nerves is most clearly visible in the case 

 of the tortoise. In this animal the ramus visceralis does not spring from the ventral 

 branch of the spinal nerve as in Mammalia, but arises directly from the ganglion on the 

 posterior root." I extract the following from the section in Gaskell's second paper 

 (p. 162), containing a definition of a complete segmental nerve : " Turning our attention 

 now to the arrangement of the fibres composing a complete segmental spinal nerve, the 

 results arrived at in my previous paper show that we must look upon both afferent and 

 efferent roots as ganglionated, for the whole argument in my former paper as to the 

 meaning of the sympathetic system was to prove that the symjwthctic ganglia are the 

 ganglia helonging mainly to the fine meduUated fibres of the anterior roots, so that we 

 must look upon a spinal nerve as possessing efferent or motor ganglia as well as aflfereot 

 or sensory ganglia. These efi'erent ganglia have, according to the observations of Onodi, 

 travelled away firom the original ganglionic mass situated on the roots of the spinal nerve, 

 so that we may term these motor ganglia ' vagrant ' in contradistinction to the ' stationary ' 

 sensory ganglia on the posterior root ; it follows then that a spinal nerve must be defined 

 as formed by (1) A posterior root composed of aflFerent fibres, both somatic and splanchnic, 

 the ganglion of which root is stationary in position and is always situated near the 



entrance of the fibres into the central nervous system " (Italics mine.) On p. 174 



Gaskell states his belief that the facial nerve of mammals " has lost its primitive stationary 

 ganglion and the afferent fibres in connection with that ganglion ; I would therefore look 

 upon the existing sensory distribution of the nerve [cp. particularly p. 173] as belonging 

 to the same system as that of the Vth : i. e., as already mentioned, a system of sensory 

 nerves which has taken the place of the lost sensory elements of the primitive group of 

 segmental nerves." I shall give, further on, reasons for doubting Gaskell's latter 

 statements. 



In 1890 an important work was published by Chevrel (1887-90, 41) on the sympa- 

 thetic nervous system of Fishes. This author states tliat in the bony fishes the first 

 sympathetic ganglion is always associated ivith the "trigeminus" and lies under the 

 Gasserian ganglion. The second sympathetic ganglion is described as follows (p. 179) : — 

 " Le 2" ganglion cephaliqne est place sous le facial ou en arriere de ce nerf qui lui envoie 

 ses racines. II emet tin ou deux filets pour le facial et ses ramifications ; il en emet 

 tonjours un autre pour le rameau anterieur du glossopharyngien." (Italics author's.) It 

 seems from these quotations that the facial ganglion of the Cod may represent Clievrel's 

 first and second ganglia fused. In the Physostomi Cheviel makes the remarkable and 

 interesting statement that the visceral branches of the vagus are all connected with the 

 first sympathetic ganglion, which in the case of these fishes is attached to the vagus and 

 not to the trigeminus. 



