CLASSES OF M0VP:MENTS 133 



the leg is drawn into the cross-legged position. To place 

 the leg in this position requires an extensive motion, 

 and therefore a long muscle. The tailor's muscle is 

 in fact the longest muscle in the body, starting as it 

 does in the trunk above the hip joint and extending 

 across the front of the thigh and over the knee to an 

 insertion on the inner side of the leg just below the 

 knee. 



Classes of Movements. — Although the movements 

 of any animal are both numerous and varied, those 

 that are visible from the outside fall into six classes 

 as follows : (a) Posture. This is more significant in two- 

 legged forms like man and birds than in the four-legged 

 animals which have a steadier base. A man who is stand- 

 ing erect, even though he be a soldier at attention, makes 

 balancing movements almost continuously. They are 

 usually so slight as to be observed only by careful watch- 

 ing, (b) Locomotion. Under this head we include all 

 bodily motions whose effect is to transport the body from 

 one point to another, (c) Grasping, which includes all 

 movements by which materials are seized or handled. 

 These movements are of first importance in the securing 

 and taking in of food. So closely related to the grasping 

 movements that they cannot well be separated, are the 

 forcible outward movements of the arms which take place 

 in striking, (d) Chewing and swallowing. These are 

 again motions which are primarily concerned with the 

 taking of food, although in many of the lower animals 

 the motions of biting enter also as a part of combat, (e) 

 Sense perception. Under this head are included move- 

 ments of the eyes, of the external ears in such animals 

 as have movable ears, of the nose in sniffing, and perhaps 

 a few others. (/) Voice production and breathing. All 

 the higher animals make movements of breathing and 

 in those among them that have voice the movements of 

 breathing and of voice production fall under a single 

 head. There are not many motions which cannot be 



