TRANSMISSION OF THE EXCITEMENT. 113 



and the elastic extension (see fig. 8, p. 26). This part 

 is omitted in fig. 28, in order to make the indicating 

 phxte more visible. The rate at which the plate flies 

 from A to B at first increases up to the point at which 

 the spring exceeds the position in which it was when at 

 rest. When the frame is in the position corresponding 

 with this point, a projection d, which is situated on the 

 lower edge of the frame, strikes the lever h and thus 

 opens the main current of an induct orium, by which an 

 inductive ciu-rent is caused in the secondary coil of the 

 inductorium ; and this traverses and irritates the muscle. 

 The result of this is that the muscle is irritated exactly 

 at the moment at which the glass plate assumes a 

 definite position relatively to the indicating pencil of 

 the lever. If the glass plate is first pushed toward A, and 

 is then slowly pushed toward B, until the projection d 

 just touches the lever, and if the muscle is then caused 

 to pulsate, the indicating pencil, being raised by the 

 pulsation, describes a vertical line, the height of which 

 represents the height of elevation of the muscle. If 

 the glass plate is again brought back to A, and, by 

 pressing the trigger, is then caused to fly suddenly and 

 with great speed toward B, then the irritation of the 

 muscle will occur wiien the glass plate is in exactly the 

 same position, the indicating pencil standing exactly 

 at the vertical stroke before described. The muscular 

 pulsation thus produced will, however, in this case be 

 indicated on the rapidly moving glass plate, with the 

 result of giving, not a simple vertical stroke, but a 

 curved line. The distance of the point of commence- 

 ment from the vertical stroke expresses the latent 

 irritation. 



If, instead of irritating the muscle itself, a point 



