294 ENDOCRINE GLANDS 



ganglionic cells, which cells give rise to ganglion-organic 

 axions made up of gray fibres. Some of these axions go 

 to the periphery (ganglion-somatic fibres) joining by 

 means of the gray rami communicantes the spinal nerve, 

 while others reach the viscera by means of the splanchnic 

 vegetative nerves ganglion-splanchnic fibres. 



We have also studied the various ways the central 

 ganglionic fibres end, the origin and ending of the ganglion- 

 splanchnic fibres ; finally, we have studied the commissural 

 fibres. It is, therefore, easy for us to conclude that the 

 thoracic-lumbar part of the vegetative system, the real sympa- 

 thetic is made up of: 



1. A central motor, medullary part, the vegetative 

 intermediolateral column, included between the I, II 

 dorsal segment and the III, IV lumbar. 



2. Central ganglionic fibres which by means of the 

 white rami communicantes of the nerves corresponding to 

 these segments, reach a ganglion belonging to one of the 

 three rows of ganglia (vertebral row, visceral row, paren- 

 chymatous row). 



3. Ganglion-organic fibres, somatic or visceral, which 

 arise: 



(a) From the ganglia of the lateral chain for the somatic 

 distribution; 



(6) From any one of the three rows for the splanchnic 

 distribution. 



The diagrams attached to this book explain this far 

 better than any long description: 



(a) The general disposition of the thoracic-lumbar or 

 sympathetic part of the vegetative system; 



(6) The topographical distribution of the nerves of 

 this system ; 



(c) The relationship of these endings with their medul- 

 lary origin. 



