240 



Presents. 



[Feb. 



Excitation of the Spinal Cord. Whereas in the foregoing series (I) 

 MV dealt only with ascending impulses, we proceeded to investigate 

 the distribution of descending impulses by observing the above-named 

 changes when the individual columns of the cord are excited by 

 minimal and later with more intense stimuli, controlling our results 

 by the method of intervening sections. 



We can summarise the effects observed as follows : 



(1.) Marked quantitative diminution suffered by impulses, leaving 

 the spinal cord by the anterior roots, whether originating in the 

 cortex cerebri, corona radiata, or the lateral columns of the cord. 



(2.) Localisation of direct transmission of impulses in the posterior 

 column and passing out into the posterior roots of the same side. 



(3.) Proportionate development of the direct and indirect paths in 

 the individual columns of the cord, passing out into the mixed nerve 

 of the one side. 



(4.) Effects observed in the posterior roots when the bulbo-spinal 

 centres are excited either by strychnine or electrically (kinaesthesis). 



Finally, the chief general principles elucidated by this research may 

 be stated as follows : 



(1.) Unilateral character of the representation of function in the 

 paths of the central nervous system. 



(2.) The physiological characteristics of the regions of a nerve 

 centre : 



(a.) The kinsesthetic activity of the afferent region of the centre. 

 (6.) The obstruction offered by the efferent region, including the 



field of conjunction, to the transmission of impulses through 



the centre. 



Presents, February 26, 1891. 

 Transactions. 



Baltimore : Johns Hopkins University. Studies in Historical 



Political Science. Series 9. No. 1 II. 8vo. Baltimore 1891 



The Univenrit 



Cracow : Academic des Sciences. Bulletin International. Comj 

 liendus des Seances. 1891. No. 1. 8vo. Cracovie. 



The Acader 

 Delft : Ecole Polytechnique. Annales. Tome VI. Livr. 2. 



Leide 1890. The 



Dublin : Royal Irish Academy. Transactions. Vol. XXK 



Part 14. 4to. Dublin 18i)l ; Proceedings. Ser. 3. Vol. I. 



No. 4. 8vo. Dublin 1891. The Academy. 



