488 PSYCHOLOGY. 



A supply of ideas of the various movements that are possible 

 left in the memory by experiences of their involuntary perform- 

 ance is thus the first prerequisite of the voluntary life. 



Now the same movement involuntarily performed may 

 leave many different kinds of ideas of itself in the memory. 

 If performed by another j)erson, we of course see it, or we 

 feel it if the moving part strikes another part of our own 

 body. Similarly we have an auditory image of its effects 

 if it produces sounds, as for example when it is one of the 

 movements made in vocalization, or in playing on a musical 

 instrument. All these remote effects of the movement, as 

 we may call them, are also produced by movements which 

 we ourselves perform ; and they leave innumerable ideas 

 in our mind by which we distinguish each movement 

 from the rest. It looks distinct ; it feels distinct to some 

 distant part of the body which it strikes ; or it sounds dis- 

 tinct. These remote effects would then, rigorously speak- 

 ing, suffice to furnish the mind with the supply of ideas 

 required. 



But in addition to these impressions upon remote or- 

 gans of sense, we have, whenever we perform a movement 

 ourselves, another set of impressions, those, namely, which 

 come up from the parts that are actually moved. These 

 kincesthetic impressions, as Dr. Bastian has called them, are 

 so many resident effects of the motion. Not only are our 

 muscles supplied with afferent as well as with efferent 

 nerves, but the tendons, the ligaments, the articular sur- 

 faces, and the skin about the joints are all sensitive, and, 

 being stretched and squeezed in ways characteristic of each 

 particular movement, give us as many distinctive feelings 

 as there are mc ements possible to perform. 



It is by these resident impressions that we are made 

 conscious of passive movements — movements communicated 

 to our limbs by others. If you lie with closed eyes, and 

 another person noiselessly places your arm or leg in any 

 arbitrarily chosen attitude, you receive an accurate feeling 

 of what attitude it is, and can immediately reproduce it 

 yourself in the arm or leg of the opposite side. Similarly 

 a man waked suddenly from sleep in the dark is aware of 

 how he finds himself lying. At least this is what happens 



