384 THE OUTGO OF ENERGY 



main as before. Kepeat the preceding experi- 

 ment but tell the subject to signal only when 

 the tongue (or hand) is stimulated. In order to 

 do this he must add to his former reaction a de- 

 cision as to the part stimulated. 



Reaction time with choice is longer than sim- 

 ple reaction time. In general, the more compli- 

 cated the mental processes involved, the longer 

 will be the reaction time. 



INHIBITION OF REFLEXES 



Through Peripheral Afferent Nerves. Expose 

 the left sciatic nerve for a distance of about 15 

 mm. in a frog the brain of which has been de- 

 stroyed. Tie a thread around the distal end, and 

 sever the nerve at the peripheral side of the liga- 

 ture. Place the central stump of the nerve on 

 the electrodes of the inductorium, the short-cir- 

 cuiting key being closed. Make the primary 

 circuit, and set the hammer vibrating. Now open 

 the short-circuiting key, bring the right foot of 

 the frog into the dilute sulphuric acid up to the 

 ankle, and count the seconds from the moment 

 of immersion to the moment of withdrawal, con- 

 tinuing meanwhile the stimulation of the central 

 end of the left sciatic nerve. 



The latent period will be much prolonged. 



Wash off the acid carefully. 



