428 



MESSRS. F. GOTCH AND V. HORSLEY 



Result of Hemisection. 

 EXCITATION on same side as Section. 



EXCITATION on opposite side to Section 



Tn Cat (a) the cord was divided and prepared at the lower border of the 9th dorsal 

 vertebra, and the section made at the 13th dorsal. In Cat (6) the cord was divided 

 and prepared at the 9th dorsal. Both sciatic nerves were prepared, and first one and 

 then the other excited in the manner previously described. The stimulus was in the 

 above cases that of the Helmholtz side- wire, 100 stimuli per second, continued for 

 5 seconds with an intensity just sufficient to evoke slight reflex effects in the lower 

 part of the cord, i.e., the secondary coil was placed at 500 or 1000. The ratio of the 

 sum of the two different columns indicates that an intervening hemisection, when on 

 the same side as the excited nerve, will diminish the cord effect 77 per cent., and 

 that when it is on the opposite side it also diminishes the effect, but to a very much 

 less extent, namely, only 15 per cent. 



As far then as the nerve-to-cord effect is concerned, its production is very largely 

 dependent upon the unbroken integrity of the fibres and grey matter along that side 

 of the spinal cord with which the stimulated nerve is connected. 



