280 ENDOCRINE GLANDS 



part of the fibres constituting this nerve (Xth); from 

 the nuclei of the musculo spinal, fibres which go 

 with the preceding nerve; finally from the organic nucleus 

 of the hypoglossus, arise fibres which follow this nerve 

 (XII cranial). 



In the cervical region, the vegetative column, gives 

 birth to fibres which follow the course of the musculo 

 spinal fibres which we have just said, reach the vagus. 



In the thoracic and lumbar region the organic column 

 gives birth to fibres which go out in segments with the 

 mixed spinal nerves arising between the I dorsal and III 

 lumbar. These vegetative fibres are the white rami 

 communicantes of the sympathetic and do not exist in any 

 other region. 



In the sacral region a certain amount of vagueness exists 

 as to the exact part played by the two columns: the 

 median ventral column arid the intermediate lateral 

 column. One fact, however, is definite and that is that 

 some sacral segments, chiefly those of the II, III, IV 

 segments, give birth to vegetative fibres which constitute 

 the erector plexus (it is best because of its very general 

 functions to call it the vegetative pelvic plexus). Outside 

 of this fact, what is the relative importance of the median 

 ventral column and the intermediate lateral column in the 

 constitution of the pelvic plexus? Logically, we are led to 

 believe that the intermedio lateral column gives to the 

 pelvic plexus analogous fibres to those which they give 

 off at the cervical portion and which are incorporated with 

 the vagus; fibres which in the lumbar and thoracic part, 

 reach both the lateral ganglia and those further located. 

 Such are the anatomical facts. From a physiological point 

 of view, we shall soon see that the vegetative fibres issued 

 from the intermediate lateral column in the cervical, and 

 the thoracic and lumbar region have different functions, 



