viii Journal of Comparative Neurology. 



shock. During the period of observation after operative procedure was 

 finished the narcosis was gradually diminished. 



Sufnmary : The resting electrical difference between the cut and 

 uninjured longitudinal surfaces of the mixed nerve is .01 Daniel (cat) 

 or .005 Daniel (Monkey), in the case of nerve root, or .025 (cat); in the 

 case of cord, .032 (cat) or .022 (monkey). The difference in the cord is 

 increased during its function and is more pronounced when it is connected 

 with encephalon. 



The excitatory state evoked by cortical activity undergoes a diminu- 

 tion of over 80 per cent, in the passage from the cord into the sciatic nerve. 



By applying the galvanometiic method to differentiate the cortical 

 excitable areas, by comparing the discharges from the same in the spinal 

 cord, a striking degree of localization was demonstrated. 



The effect of excitation of the corona radiata on the cord is only half 

 that of the cortex and the efHect in the sciatic is but one fourth that of the 

 cord. It is possible to produce strictly unilateral effects in cord and 

 sciatic nerve from complete excitation of cortex cerebri and corona radiata, 

 but the circumstances which favor bilateral effects are such as bring into 

 play the opposite hemisphere, cerebellum, basal structures, etc. The 

 normal condition is unilateral. 



In the monkey a relatively larger number of direct fibres are contained 

 in the lateral column than in the posterior, while in the cat the reverse is 



the case. 



For both classes of impulses and animals observed no evidence was 

 obtained of crossing between lateral columns l)ut evidence of indirect con- 

 nections between one posterior column and the lateral column of the same 

 side, and evidence of cross connections between the posterior columns. 

 Tliere is no evidence of any continuous fibres between the mid-dorsal and 

 lumbar regions. 



By far the majority of afferent impulses ascend tlie cord on the same 

 side as the root, a small minority ascend by the posterior column of the 

 opposite side. The direct path is in the posterior column of the same side, 

 the indirect paths in the posterior columns of both sides and the lateral 

 column of the same side. 



Descending electrical effects occur as follows: On minimal excitation 

 of the posterior column, impulses are directly transmitted into the pos- 

 terior roots of the same side and so into the nerve. On maximal excitation, 

 impulses are transmitted by indirect paths across the posterior roots of 



