xvi LIST OF ILLUSTRATIONS. 



PAGE 



FIG. 



119. Method of expressing the position of a point in reference to two co- 



ordinate axes . ... • • • • • 229 



120. Method of measuring the angular displacement of the arm from a 



primary vertical position . ... • • • 230 



121. Method of determining the position of a point in reference to three co- 



ordinate planes . . . • • • • .231 



122. Showing the position of the centre of gravity of the whole body and of 



the head, and also the position of the centres of rotation of the chief 

 joints (Braune and Fischer) ...... 232 



123. Method by which the axis of rotation of a ball-and-socket joint is 



determined ........ 236 



124. Method of finding the position assumed by a point when a limb is 



rotated ......... 236 



1 25. Method of compounding axes of rotation ..... 237 



126. Method of determining the centre of rotation of a joint . . . 237 



127. Illustrates the fact that a screw is an inclined plane wrapped round the 



surface of a cylinder ....... 239 



128. To show the geometrical construction of a saddle-shaped joint . . 240 



129. To illustrate the formation of an ellipsoidal joint . . . 241 



130. Curves of extension of resting and contracted muscle . . . 242 



131. „ „ „ „ „ . . . 246 



132. Jerk contractions ; tracings from the gastrocnemius muscle of a frog 



by the pendulum myograph ...... 248 



133. Jerk contractions ; tracings of the movements of the human finger-tip 



taken with the pendulum myograph ..... 248 



134. Cheese maggots, from an instantaneous photograph . . . 249 



135. Illustrating the position of the common centre of gravity of the hand 



and lower arm ........ 249 



136. Represents the rotation of a rod around a fulcrum . . . 250 



137. Illustrates Weber's theory of the movements around the ankle-joint . 251 



138. „ the method of calculating movements around the ankle- 

 joint ......... 252 



139. Represents the metbod of calculating movements when the forces are 



oblique to the axes of the body on which they act . . . 252 



140. Illustrates the change in the centre of gravity of the body when the 



heels are raised ........ 253 



141. To represent the moments around the ankle-joint . . . 253 



142. Illustrates the resolution of moments into their components . . 254 



143. Illustrating the resolution of the force of contraction of a muscle into 



three forces ........ 255 



144. Represents the action of the triceps and brachialis upon the humerus 



and ulna ......... 256 



145. Apparatus for determining the centre of gravity of the body . . 259 



146. Posture of the body with the centres of rotations of the principal joints 



in the same vertical plane ...... 260 



147. To show the position of the centre of gravity in each of the three 



postures ......... 261 



148. Centre of gravity and centres of rotation in a soldier at attention . 262 



149. To show the effect of a push in overturning the body, which is viewed as 



a rigid body resting upon the feet ...... 263 



150. Shows the area of underpropping and the plumb of the centre of 



gravity ......... 263 



151. Shoe for indicating when a man's foot comes in contact with the ground 



(Marey) ......... 264 



