ON VOLUNTARY MOVEMENTS. 681 



those cells, and that these motor impulses travel straight down the pyram- 

 idal tract to the motor fibres of the appropriate nerves, undergoing possibly 

 some change at the place in the cord where the pyramidal fibre makes junc- 

 tion with the fibre of the anterior root, but deriving their chief if not their 

 whole coordination from the cortex itself, that is to say, being coordinated 

 at their very starting-point. That such a view is untenable and that the 

 simplicity of the electrical phenomena is misleading is shown by the follow- 

 ing two considerations among others : On the one hand, as was shown in a 

 previous section, the coordination of movements may be carried out apart 

 from the cortex, namely, in the absence of the hemispheres ; and we can 

 hardly suppose that there should be two quite distinct systems of coordina- 

 tion to carry out the same movement, one employed when volition was the 

 moving cause, and the other when something else led to the movement. On 

 the other hand, the analogy of speech justifies us in concluding that the cor- 

 tical processes do take advantage of coordination effected by the action of 

 other parts of the nervous system. 



Bearing this in mind, we may recall attention to the remarkable effects 

 which result from the removal of the area. These are twofold. In the first 

 place, there is more or less complete paralysis of the limb ; all the movements 

 of the limb are for a time ineffective. It is not that purely voluntary move- 

 ments are alone, so to speak, cut out ; the reflex and other movements are 

 also impaired or temporarily abolished, and, as we have already said, in 

 many cases at least the sensations of the limb are interfered with. These 

 troubles are, of course, in part the effects of the mere operative interference 

 belonging to what we spoke of in 495, as being of the nature of shock. 

 But, even giving full weight to this consideration, there remains the fact that 

 the cortical area is associated with the various coordinating and other ner- 

 vous mechanisms belonging to the limb by such close ties that these are 

 thrown into disorder when it is injured. And side by side with this we may 

 put the remarkable fact previously stated, that during an abnormal condi- 

 tion of the cortical area stimulation of the area, instead of producing the 

 appropriate movements confined to the limb, may give rise to movements 

 of other parts culminating in epileptiform convulsions. 



In the second place, this paralysis is temporary only ; the voluntary move- 

 ments are after a while regained, and that in spite of the fore-limb moiety of 

 the pyramidal tract permanently degenerating along its whole length, neither 

 it nor the cortical area ever being regenerated. This shows that whatever 

 be the chain of events in the intact animal, it is possible for the " will " of 

 the animal to get at the muscles and motor mechanisms of the fore limb by 

 some other path than that provided by the appropriate cortical area and 

 corresponding path of the pyramidal tract ; and the facts previously recorded 

 ( 571) show that that other part is not the corresponding part of the pyram- 

 idal system belonging to the other half of the hemisphere, and, indeed, is 

 not any part at all of the whole pyramidal system. The " will," whatever 

 be the processes by which it takes origin, and wherever be the place where 

 they are carried on, is able in the absence of the pyramidal system to produce 

 its effect on the motor fibres of the brachial nerves by working on other 

 parts of the central nervous system. 



Hence while admitting, as we must do, that in the intact animal the cor- 

 tical area and pyramidal tract play their part in carrying out voluntary 

 movements, their action is not of that simple character supposed by the view 

 referred to above. On the contrary, we are driven to regard them rather as 

 links, important links, it is true, but still links in a complex chain. As we 

 have already urged, we may probably speak of the changes taking place in 

 the pyramidal fibres as being on the whole of the nature of efferent impulses; 



