I02 THE SPINAL CORD AND CEREBELLUM 



Their 

 functions 

 and cou- 

 nections. 



tissue of the viscera, vaso-motor to the bloodvessels, 

 and chemico-sensory to the mucous membranes or 

 tissues where the chemical processes of digestion and 

 metabolism are started. Besides the fibres proceeding 

 from the ganglia of the sympathetic system there are 

 others which affect the calibre of the visceral blood- 

 vessels.* Eeferring to the abdominal splanchnics, 

 which are mainly sympathetic, Foster says : ' The 

 majority of these splanchnic fibres seem to be efferent 

 in nature, carrying impulses from the central nervous 

 system to the tissues, some ending in plain muscular 

 fibres, others in other ways ; but some of the fibres 

 are afferent, and convey impulses from the viscera to 

 the central nervous system, and it is probable that 

 some of these begin or end in epithelial cells of the 

 viscera.' t 



Passing now from the common trunk of a spinal 

 nerve, embracing as it does fibres from the muscles, 

 bloodvessels, and sensory surfaces of, in some cases, 

 both the limbs and viscera, and in other cases of the 

 body and viscera, it will be interesting to follow as far 

 as possible the distribution of the various strands of 

 fibre in the nerve-roots. The anterior root contains 

 fibres which proceed to the skeletal muscles and to the 

 muscular tissue of the bloodvessels, and others which 

 are said to be secretory.! Whilst some of its fibres 

 come directly from the large cells of the ventral horn 

 of gray matter, others can be traced to the small cells 



* Foster, loc. cit., p. 172. 



t Ibid. t Ibid., p. 949. 



