SYSTEMATIC ANALYSIS OF APPABATUS. 87 



296. IIIUS. A BAREFOOT BOY STEPS ON A THORN. 



flis foot must be raised quicker than thought, and the 

 Same cause that excites a sensation of pain must cause 

 Ihe ganglion to exert an influence on the contractile 

 muscles that raise the foot. 



297. IlluS. IN PLAYING AN INSTRUMENT, it IS de- 



Birable to have the familiar sounds of the oft-played 

 tones influence the motions necessary to produce the 

 succeeding ones, so that the piece may be played with- 

 out thought. 



298. THE GANGLIA OF MOTION DIFFER from those of 

 sensation, and from each other, in size, form, and position, 

 and somewhat in their internal structure; but the ra- 

 tionale of their structure or their action is but very 

 slightly understood, nor can any one say how many of 

 them there ought to be, or are. 



299. IT IS PROBABLE NOT ONLY, BUT IT SEEMS NE- 

 CESSARY, that there should be a ganglion for the produc- 

 tion of each class or group of motions, so that they 

 shall take place simultaneously ; and the distribution of 

 the nerves seems to prove this. 



300. THE SMALL BRAIN, OR CEREBELLUM, has been 

 supposed to be a Motory Ganglion, adapted to harmonize 

 the movements of all parts of the body, and adjust or 

 balance the action of all the muscles. 



301. THE MOTORY APPARATUS is conclusively 

 proved to be composed as follows : 



(Ganglia, f 



MOTORY APPARATUS < Nerves. 



(Muscles. 



302. THE MOTORY APPARATUS INCLUDES much the 

 larger part of the body by weight ; if the skeleton is 

 included, not less than three fourths. 



303. THE ELEMENTARY MOTORY APPARATUS is a 

 minute portion of brain, a correspondingly minute nerve, 

 and a muscle-cell, all of which, to be seen, must be exam- 



296. What if ? 297. What said of ? 29S. How do ? 299. What ? 

 800. What is ? 301. How composed ? 302. What does ? 803. What is t 



