COND UCTION PA THS 



779 



of the cord; others associate the different segments with each other. Axones 

 which associate the structures of the spinal cord with those of the medulla 

 oblongata may be included in this system. Many of these axones cross the mid- 

 line both in the grey and in the white substance to associate the neurones of the 

 two sides of the grey column. For purposes of distinction, such as cross the mid- 

 line are called commissural fibres, while those which course upward and down- 



FiG. 616 — Continued. 



Sacral IV 



Coccygeal 



ward on the same side are association fibres. Coursing in longitudinal bundles 

 about the grey figure, the latter compose the fasciculi proprii or 'ground bundles' 

 of the spinal cord. 



METHODS BY WHICH THE CONDUCTION PATHS HAVE BEEN 



DETERMINED 



. A purely anatomical examination of a normal adult cord, prepared by whatever means, 

 gives no mdication of the fact that the mass of longitudinally coursing fibres of the white sub- 



