600 



APPENDIX 



TIME RELATIONS IN NERVOUS PROCESSES 



Determine accurately by repeated trials the time in seconds re- 

 quired for a single revolution of the kymograph drum at its highest 

 speed. Be careful to use this determined speed in the observations 

 below. Each experiment requires a subject and an operator. 



Simple Reaction Time. Arrange the inductorium for single 

 shocks, and select a strength of stimulus distinctly felt on the 

 tongue at the break of the primary circuit. The apparatus is so 

 arranged that the operator can make and break the circuit at 

 one place and the subject at another (see diagram, Fig. 157). A 

 signal records on the drum the instant of making and breaking 



FIG. 157. Diagram of reaction time apparatus. K' and K", keys for making 

 or breaking primary circuit; C, dry cell; /, inductorium; T, wires to tongue elec- 

 trodes; S, signal magnet, writing on drum. 



the circuit. Let the subject press the electrodes on his tongue, 

 place his hand on his key, and close his eyes. The operator should 

 now start the drum at known speed and close the circuit at his 

 contact. While the drum is in motion the operator should break 

 the circuit at his contact. This break shock stimulates the subject. 

 The instant the stimulus is felt the subject should close his key. 

 The points of stimulus and of response are shown in the record 

 traced by the signal on the drum. Repeat the experiment several 

 times with each member of the pair acting as subject. After the 

 tracing has been varnished measure with care the length of each 

 reaction record. By comparing these lengths with the drum cir- 

 cumference compute the reaction times in hundredths of a second. 

 Average the results from each individual. 



