274 ENDOCRINE GLANDS 



III. THE COMPONENTS OF THESE SYSTEMS. 



What are the various anatomical and physiological 

 components of these systems? 



This is the question which we are now going to study. 



We must in the vegetative, as well as in the other 

 system, describe: 



1. Higher centres. 



2. Spinal centres. 



3. Peripheral nerve fibres and, this is particular to the 

 vegetative system. 



4. Ganglia interrupting the motor tracts. 



THE HIGHER CENTRES OF VEGETATIVE LIFE. 



As 1 have shown previously and as it occurs in 

 the animal system, these higher centres are located in the 

 anterior lobe, Avhich, as we know, is divided into two parts. 



Telencephalus Hemispheres. 



Diencephalus or thalamencephalus optic layer. 



It is both in the cerebral hemispheres and in the optic 

 layers that we must look for these centres. They are 

 superimposed to the animal centres, but their exact 

 location is not yet exactly determined. W 7 hat is certain, 

 however, is that, from a physiological point of view, and 

 speaking very generally, the cortex and the medulla 

 contain centres which when stimulated react on the 

 vegetative system. From these centres arise fibres 

 destined to reach the spine and which pass through the 

 internal capsule, as do the fibres of the voluntary system. 

 Needless to say, that in the cortex also end the long 

 sensory fibres of the vegetative system. From this we 

 may conclude that: the higher centres of the anterior 

 lobes contain both centres of the voluntary and involuntary 

 nervous systems. These centres are physiologically 



