THE MUSCULAR SENSE. 593 



be well to point out that we do not refer a muscular sensation 

 to any given muscle or muscles : it is merely associated with a 

 certain movement or position, and a person who knows noth- 

 ing about his ocular muscles can judge distance through sen- 

 sations derived from them, quite as well as any anatomist. 

 This fact is of course correlated with the fact that in voluntary 

 movement we do not make a conscious effort to contract any 

 particular muscles : the higher nerve centres are merely con- 

 cerned with the initiation of a given movement of a given ex- 

 tent, and all the details are carried out by lower co-ordinating 

 centres. In ordinary daily life in fact we have no interest 

 whatever in a muscular contraction per se ; all we are con- 

 cerned with is the result, and consciousness has never had need 

 to trouble itself, if it could, with associating a particular feel- 

 ing or a particular movement with any individual muscle. 



Muscular feelings are, as already pointed out, frequently 

 and closely combined not only with visual but also with tactile, 

 in providing sensations on which to base judgments : in the 

 dark, when an object is of such size and form that it cannot 

 be felt all over by any one region of the skin, we deduce its 

 shape and extent by combining the tactile feelings it gives rise 

 to, with the muscular feelings accompanying the movements 

 of the hands over it. Even when the eyes are used the sen- 

 sations attained through them mainly serve as short-cuts which 

 we have learned by experience to interpret, as telling us what 

 tactile and muscular feelings the object seen would give us if 

 felt ; and, in regard to distant points, although we have learnt 

 to apply arbitrarily selected standards of measurement, it is 

 probable that distance, in relation to perception, is primarily 

 a judgment as to how much muscular effort would be needed 

 to come into contact with the thing looked at. 



When we wish to estimate the weight of an object we al- 

 ways, when possible, lift it,'and so combine muscular with 

 tactile sensations. By this means we can form much better 

 judgments. While with touch alone just perceptibly differ- 

 ent pressures have the ratio 1:3, with the muscular sense 

 added differences of ^ can be perceived. 



