CEREBRAL MOTOR CONTROL 45 



and nerves of the paralyzed side (experiment 5), although the 

 recovery is rapid in such a case if treatment by muscle stimu- 

 lation and nerve vibration be directed to the involved parts and 

 if special stimulation exercises be given to the animal which will 

 provoke the animal to move the paralyzed segments (final part 

 of experiment 5). The method of treatment recommended by 

 neurologists, general massage, does produce a slight amount of 

 improvement but not to an extent to enable the animal to use 

 the arm and hand properly for such ordinary operations as feed- 

 ing and climbing, although these activities may be carried out 

 after such treatment in an awkward manner. When, however, 

 efforts are directed to the special nerves and muscles, and when 

 the sound side of the animal is restrained so that movements of 

 climbing and feeding must be made, if at all, by the use of the 

 paralyzed segments the improvement is rapid and the recovery is 

 practically complete (experiments 1, 4, and 7). 



One fact that stands out prominently is that recovery from 

 the hemiplegic state may be very rapid. It has long been 

 known that an hemiplegic monkey left to its own devices will 

 after a considerable period of time recover the ability to use the 

 arm and leg, but this period is one of months and is well illus- 

 trated in the one of the experiments described (experiment 2), 

 where the animal after six months has not recovered to any 

 great extent the ability to use the paralyzed left side. The 

 rapid recovery of the animals used in experiments 1, 4, and 7, 

 and in the last part of experiment 5, is suggestive, and perhaps 

 conclusion-compelling, that the continued paralysis of animals, 

 and by analogy the persistence of motor incapacities in man, 

 is due to lack of management rather than to a real inability. 8 



The results also suggest a reconsideration of the whole prob- 

 lem of cerebral motor control, and especially that of cortical 

 motor control. It has long been believed and taught that the 

 cerebral cortex is necessary for the production of a voluntary 



6 Each of the authors has in preparation a report of a series of cases of paraly- 

 sis in man which will be published shortly, both showing that considerable im- 

 provement may result from properly directing the attack against certain muscle 

 groups and their related nerves. 



