CHAPTER X. 



ACTION OF THE SPINAL CORD AS A CONDUCTOR. 



Transmission of motor stimulus in the cord Decussation of the motor conduct- 

 ors of the cord Decussation at the medulla oblongata Decussation of the 

 motor conductors in the cervical portion of the cord Transmission of sen- 

 sory impressions in the cord The white substance of the posterior columns 

 does not conduct sensory impressions Action of the gray matter as a 

 conductor Probable function of the cord in connection with muscular 

 coordination Decussation of the sensory conductors of the cord Summary 

 of the action of the cord as a conductor. 



IN treating of the functions of the spinal cord, both as a 

 conductor and as a nerve-centre, we shall endeavor to discuss 

 those facts only which are, it is to be hoped, either defini- 

 tively settled, or are in accordance with what is at present 

 known in anatomy, physiology, and pathology. The litera- 

 ture upon this portion of our subject is so extended and 

 diffuse, that a full, critical analysis of the different experi- 

 ments and views that have been presented since the obser- 

 vations of Magendie, in 1823, would inevitably complicate 

 and confuse our description. "We shall give citations, how- 

 ever, which will enable the reader to refer readily to the 

 most reliable historical and controversial discussions upon 

 this subject. 1 



1 Longet, in his treatise on physiology, gives a tolerably complete historical 

 account of the numerous experimental researches concerning the functions of 

 the cord as a conductor ( Traite de physiologic, Paris, 1869, tome iii., p. 338, et seq.\ 

 The writings upon this subject by Brown-Sequard are very voluminous, and are 

 scattered through numerous periodical publications, while many of his papers 

 are controversial, and are reiterations of experiments and views previously pub- 



