334 



THE SENSES 



house chiefly because in de Pachmann this sense we are considering is 

 developed to its human limit, while in her apparently it is not. 



Another use of the muscular nerve-impulses combined with those from 

 the tendons, joints, etc., is the direction of the power of contraction need- 

 ful to overcome a required resistance, as, for example, that of gravity in 



FIG. 188 



Afferent 

 Cerebral. 

 Efferent. 



1 Joint 



2 Muscle 



3 Tendon 



4 Skin 



Diagram of the chief kinesthetic nerve-impulses. From the joints, muscles, tendons, and 

 skin nervous influences pass inward and upward to the "motor centers" of the cord and brain, 

 making general connection with the cerebellum on the way. Numerous "central" impulses 

 connect these incoming messages with other parts of the brain, motor and sensory, and especially 

 with the regions which control the efferent influences to muscle and to epithelium. The 

 impulses passing down and out likewise have much to do with the cerebellum. This whole 

 apparatus together end-organs, afferent influences, centers, central impulses, efferent influences, 

 and muscles constitutes the neuro-muscular mechanism. 



lifting a weight. This estimate is made by the intellectual "centers" of 

 the brain, but only from repeated experiences given through the afferent 

 muscular and other senses. The effort is expended under the guidance 

 of impulses coming from the contracting muscle. 



That kinesthesia has separate centers somewhere in the brain, or 

 else separate paths up the cord, is made evident by the occasional cases in 



