ORGANIC MOVEMENTS 101 



reactions, and therefore a full discussion is not required. 

 Indeed the fact that there are but three sound legs is 

 an item in the sum of the motor stimuli and conditions 

 just as a carriage crossing the path of our dog would 

 be ; it forms part of the " individualised stimulus/' 

 according to which the individuality of the action is 

 determined. But any one who prefers it might also gain 

 an independent proof of autonomy from this kind of 

 motor regulation, by saying that, besides the individual 

 correspondence between the stimulus proper and the action, 

 a correspondence of an individualised type is also going 

 on between the specified state of the motor organs and 

 the specified use of them. In some way, of course, it 

 is to the brain again that this regulation relates ; other 

 centrifugal nerves are used for one and the same action, 

 according to what kind of abnormal state the motor organs 

 are in. 1 



A very interesting clinical experiment, carried out by 

 Vulpius, deserves mention in this connexion. The tendon 

 of a flexor muscle of the foot was split and one of its 

 halves was made to heal in such a way that it could 

 perform the function of stretching the extensor muscle 

 being paralysed. After a certain time, in fact, the 

 flexor muscle was " split " also physiologically : part of 

 it was used for bending, part for stretching, as circum- 

 stances required. In a very strange and perfect manner 

 the " acting principle " had succeeded here in using quite 

 an abnormal centrifugal nerve, and, of course, quite 



1 Ophiurids deprived of one or more arms also show good instances of 

 this class of regulability in movement. Compare Preyer's experiments, which 

 I have most completely confirmed myself. 



