MUSCULAR SENSE. 293 



That is, when reduced to its simplest terms, our most practi- 

 cal and important knowledge of the world is the outgrowth of 

 tactile and muscular perceptions ; by and with them all other 

 sense-perceptions have been corrected and compared. 



" The fundamental education concerning the outer world, 

 which engages the earliest years of every child, consists in 

 accumulating and systematizing with other sense-perceptions 

 tactile and muscular impressions of objects. A sensation is 

 no sooner felt than some muscular movement, involving a 

 definite muscular feeling, is made by which the character of 

 the sensation is changed and experimentally tested under 

 different conditions. The physiological process involved in 

 building up sense-knowledge, therefore, embraces in alterna- 

 tion sensation excited by external objects, motion accompanied 

 by muscular sensation, and change in original sensation. In 

 other words, the motor and sensory impulses form a sort of 

 balance, and both are necessary. 



" When we consider that it is through muscular sensation 

 that we derive our most accurate conceptions of the form, 

 weight, and position of objects, and through which we explore 

 our own body surface, and distinguish its areas of localiza- 

 tion ; that this is the fundamental sense by which the sensa- 

 tions arising in most other organs are tested and verified, and 

 that it is from the sense of muscular movement that we can 

 form ideas of time and space, it may well be regarded as the 

 mother of all sense-perceptions. Normal muscles, even when 

 functionally inactive, are still in a state of tonic contraction ; 

 it is not improbable that this tone is a reflex action whose 

 sensory element is formed by the impulses traveling along 

 nerves of muscular sensation. Such impulses are probably 

 indispensable to the preservation of the equilibrium of the 

 body." SEWALL. 



An illustration of the assistance which touch and the mus- 



