SYMPATHETIC ]S T ERYE. clix 



which connects together the principal chain of ganglia, and in the primary 

 branches proceeding from thence to the viscera. In the last-mentioned 

 case the different fasciculi get more mixed as they advance, but generally it 

 is only after the white fasciculi have passed through one or more ganglia that 

 they become thoroughly blended with the grey ; and then, too, the nervous 

 cords receive a large accession of grey fibres (apparently derived from the 

 ganglia), which are mixed up with the rest, and take off more and more 

 from their whiteness. 



Relation of the sympathetic to the cerebro-spinal nerves. "We have next 

 shortly to consider the relation between the sympathetic and the cerebro- 

 spinal system of nerves. On this important question two very different 

 opinions have long existed, in one modification or another, amongst ana- 

 tomists. 1. According to one, which is of old date, but which has lately 

 been revived and ably advocated by Valentin, the sympathetic nerve is a 

 mere dependency, offset, or embranchment of the cerebro- spinal system of 

 nerves, containing no fibres but such as centre in the brain and cord, 

 although it is held that these fibres are modified in their motor and sensory 

 properties in passing through the ganglia in their way to and from the 

 viscera and involuntary organs. 2. According to the other view, the sym- 

 pathetic nerve (commonly so called) not only contains fibres derived from 

 the brain and cord, but also proper or intrinsic fibres which take their rise 

 in the ganglia ; and in its communications with the spinal and cranial 

 nerves, not only receives from these nerves cerebro- spinal fibres, but imparts 

 to them a share of its own proper ganglionic fibres, to be incorporated in 

 their branches and distributed peripherally with them. Therefore, accord- 

 ing to this latter view, the sympathetic nerve, commonly so called, though 

 not a mere offset of the cerebro- spinal nerves, yet, receiving as it does a 

 share of their fibres, is not wholly independent, and for a like reason the 

 cerebro spinal nerves (as commonly understood) cannot be considered as con- 

 stituted independently of the sympathetic ; in short, both the cerebro-spinal 

 and the sympathetic are mixed nerves, that is, the branches of each system 

 consist of two sets of fibres of different and independent origin, one con- 

 nected centrally with the brain and cord, the other with the ganglia. Hence, 

 if we look to the central connection of their fibres as the essential ground of 

 distinction among nerves, the cerebro-spinal system of nerves might, strictly 

 speaking, be considered as consisting of and comprehending all the fibres 

 having their centre in the cerebro-spinal axis, whether these fibres run in the 

 nerves usually denominated cerebral and spinal, or are distributed to the 

 viscera in the branches of the nerve usually named the sympathetic ; and, 

 on the same ground, the sympathetic or gangliouic system, strictly and pro- 

 perly so called, would consist of and comprehend all the fibres connected 

 centrally with the ganglia, wherever such fibres exist and into whatever 

 combinations they enter, whether proceeding to the viscera or distributed 

 peripherally with the nerves of the body generally ; the nerve-fibres which 

 emanate from the ganglia on the roots of the spinal and cerebral nerves 

 being reckoned into the system, as well as those from ganglia, visually deno- 

 minated sympathetic. While ready, however, to acquiesce in the justice of 

 the above distinction, we do not mean to employ the terms already in use 

 in a sense different from that which is currently received. 



In endeavouring to decide between the two views above stated, it may be first 

 observed that the existence in the sympathetic nerve of fibres connected centrally with 

 the cerebro-spinal axis, is proved not only by tracing bundles of fibres from the roots 

 of the spinal nerves along the communicating branches and into the sympathetic, but 



