1 36 /oiinial of Co)>iparative Xcurology and Psychology. 



periment almost whoU}- positive, the maximum being reached 

 when the interval between the flash and the blow was o. i"- 

 0.3". With the third individual a positive phase having its 

 maximum when the intcrxal was zero gave place rapidly to a 

 negative phase reaching its maximum at 0.4" 0.8". 



"(4) The effect of a sudden stimulus of the conjunctiva 

 b}' an air blast was in general similar to that of a visual stim- 

 ulus, except that the positive phase in all three individuals 

 reached its maximum when the interval between the blast and 

 the blow was o. I ", and the negative phase in the individual 

 who manifested this phenomenon had its maximum at 0.8"- 

 i.o"." 



The effects of sudden stimulation of the nasal mucous 

 membrane with a blast of air and of stimulation of the skin of 

 the neck were v^ery similar to those stated. 



SUMMARY AND CONCLUSIONS. 



1. Increase in light intensity from i" to 2" before electric 

 stimulation of the skin of the frog causes delay of reaction to 

 the latter stimulus. If the electric stimulus be intense the in- 

 hibitory influence, as indicated by the time of reaction, is 

 slight, if it be weak the inhibition is marked, and reaction may 

 fail entirel)'. 



2. Auditory stimuli give contradictory results. Some- 

 times they appear to inhibit, sometimes reinforce, the electric 

 reaction. In case of the sound of an electric bell introduced 

 (a) o. i" before the electric stimulus, and (b) i.o" before, the 

 average for 300 reaction-times indicate a slight inhibitory in- 

 fluence. 



3. Visual stimuli either inhibit or reinforce electric reac- 

 tions according to the temporal relation of the two stimuli. (a) 

 The visual stimulation of a moving object when given o.i" be- 

 fore electric stimulation of the skin causes reinforcement of the 

 reaction, i. e., shortens the reaction-time. (b) When given 

 0.5" or i.o" before the electric stimulus the same visual stim- 

 ulus causes inhibition, i. e., lengthens the reaction-time. 



4. The e.xperiments described prove that it is of import- 



