54 PHYSIOLOGY OF MUSCLES AND NERVES. 



point of contact, and also throug-li the primary coil of 

 an inductive apparatus. The secondary coil is con- 

 nected with the muscle. When, therefore, the lever I 

 is turned aside, the muscle is irritated. Accordingly it 

 pulsates and raises the pencil of the index so that the ^ 

 latter marks a vertical line, representing the height of 

 elevation of the muscle, on the cylinder A, By press- 

 ing the finger on g, the bayonet- shaped point I rday be 

 slightly raised, the index point e being at the same time 

 slightly removed from the cylinder. The clockwork 

 is then set in motion. The cvlinder turns, at first 

 slowly, but gradually more quickly ; but the muscle 

 remains inactive, and the point can make no mark. 

 As soon as the cylinder has attained the desired speed 

 the finger is removed ; I sinks, and is soon after caught 

 and turned aside by the nose, and the muscle, thus irri- 

 tated, pulsates, and this pulsation is recorded on the 

 cvlinder durinof its rotation. 



The irritation of the muscle being effected by the 

 apparatus itself, it occurs when the rotating cylinder 

 is in a definite position ; that is to say, the cylinder 

 is in that position in which the nose has just touched 

 the end of the lever I. It is evident that this posi- 

 tion is the same as that at which the muscle was at 

 first allowed to pulsate when the cylinder stood still. 

 The vertical line then drawn, therefore, indicates 

 exactly the position of the cylinder at the moment at 

 which irritation takes place. Where this vertical line 

 deviates from the horizontal line first drawn is the 

 point at which the pencil was when irritation was in- 

 duced in the muscle. The distances from which the 

 periods are to be calculated must be measured from 

 this point. 



