INORGANIC RESPONSE 103 
of the curve is somewhat steep, and the recovery 
convex to the abscissa, the fall being relatively rapid 
in its first, and less rapid in its later, parts. As the 
electric variation is the concomitant effect of mole- 
cular disturbance—a temporary upset of the molecular 
equilibrium—on the cessation of the external stimulus, 
the excitatory state, and its expression in electric 
variation, disappear with the return of the molecules 
to their condition of equilibrium. This process is 
seen clearly in the curve of recovery. 
Different metals exhibit different periods of recovery, 
and this again is modified by any influence which affects 
the molecular condition. 
That the excitatory state persists for a time even on 
the cessation of stimulus can be independently shown 
by keeping the galvanometer circuit open during the 
application of stimulus, and completing it at various 
short intervals after the cessation, when a persisting 
electrical effect, diminishing rapidly with time, will be 
apparent. ‘The rate of recovery immediately on the 
cessation of stimulus is rather rapid, but traces of strain 
persist for a short time. 
