286 ENDOCRINE GLANDS 



of the genito urinary apparatus, which are under the 

 dependence of the vagus and the pelvic plexus. 5 



In the second group we have the autonomous systems 

 of the heart, gastro intestinal tract, and urinary tract; 

 which are constituted of parenchymatous ganglia and 

 autonomous cells not grouped in ganglia. 



Among the parenchymatous ganglia and the intra 

 visceral nerve cells there exist (outside of the sensory cells) : 



1. Ganglionic or cellular groups wliich depend on the 

 greater systems and which practically cannot get along 

 without them; these are the long arc motor systems. 



2. Ganglionic and cellular groups relatively indepen- 

 dent of the vegetative system of the nerve axis, which can 

 be influenced by them, but can function independently 

 from them. These are the short reflex arcs which keep 

 up life in an organic segment when separated from all 

 central connection, as long as chemical media is adequate. 



To complete the study of the components of the vegeta- 

 tive system, we must also describe the glandular element, 

 the glands of internal secretion, which, by their harmonies 

 help to regulate the vegetative system. This question 

 will be stated ultimately. 



IV. ANATOMICAL AND PHYSIOLOGICAL DESCRIPTION 

 OF THE VARIOUS SYSTEMS. 



We have just seen that among the various elements of 

 the vegetative nervous system we must distinguish : 



1. Higher centres; 



2. Spinal centres; 



3. A peripheral system composed of fibres and ganglia. 



Finally, we have also seen that in the last-named group 

 there were: 



6 These two nerve elements, the vagus and the pelvic plexus, both have their ganglia 

 as near as possible to the viscera, in this way differing from the sympathetic. 



