258 Mr. J. S. R. Russell. On the Nerve Roots of 



and evidence in favour of an affirmative reply brought forward. 

 The results which have been obtained in the present investigation 

 have been in conformity with this view, so that I see no reason- to 

 .alter the opinion formerly expressed. 



A further point that was determined in this connexion was the 

 question whether, when a muscle receives nerve fibres from more 

 than one nerve root, both nerve roots supply nerve fibres to one and 

 the same muscle fibre, and evidence was adduced to negative this 

 possibility. The following evidence also negatives this view : The 

 peroneus longus muscle is supplied with nerve fibres from the 6th 

 and 7th lumbar nerve roots, and the maximum contraction which can 

 be evoked on excitation of the 6th root alone was greater than that 

 evoked by stimulation of the 7th root alone ; but neither effect was 

 as great as when both roots were simultaneously excited. Another 

 muscle chosen in order to test this point was the sartorius, which is 

 supplied by the 3rd and 4th lumbar roots. When the 3rd root is 

 excited with a minimal stimulus, the resulting contraction of the 

 muscle is limited to its upper part, while similar excitation of the 

 4th root is followed by contraction of its lower part alone. 



Part IV (Control). Alteration in the Action of the Posterior Extremity 

 in Progression in Climbing or in Standing evoked by Section of a 

 Nerve Hoot. 



The following experiments were performed in order to observe 

 the effect of division of one or more nerve roots on the movements 

 of the limb during use in ordinary progression, climbing, &c. I 

 observed the effects produced by division of a single nerve root, 

 of two or three consecutive roots, and of two or three alternate 

 roots on the same side. In no instance did 1 find that the division 

 of a single nerve root was followed by any alteration in the 

 movements of the limb, such as could be detected by running or 

 climbing, twenty-four hours after the operation. A variable amount 

 of paresis or paralysis of certain movements followed section of two 

 or more nerve roots. Section of two consecutive nerve roots produced 

 a greater effect than section of two alternate roots on the same side, 

 an intermediate root being left intact. The effect in both these cases 

 depended on the size of the roots divided, for even if the roots divided 

 were two consecutive ones, and caused great impairment of any given 

 movement, yet the effect noticeable would be much greater if the 

 roots divided were large than if they were small, for the number of 

 other movements weakened would be greater with large than with 

 small roots. I have never found that the monkey's power of grasping 

 the wire of its cage-house in climbing, after section of the 1st and 

 2nd sacral roots, has been impaired in such a manner as to be 



