Nervous accommodation of the sensitive elements of the pulp was determined in 152 teeth by measuring the accommodation index with 2 exponentially increasing currents -of different rise-times.Thirty-five teeth with pulpal necrosis were stimulated with the fastest exponentialcurrent.Clinical symptoms were investigated to compare the efficiency of electrical and clinical methods in the diagnosis of pulp disturbances.Results were checked by means of histologic examination of all the teeth studied.Accommodation index showed a high correlation with the histologic pictures of the pulps, while clinical diagnosis showed a low correlation.The accommodation indices of the normal and pathologic groups are statistically different, and decreased as disturbances increased.Eighty per cent of teeth with pulpal necrosis did not react to electric stimuli, 17 per cent gave a response to more than 100 volts, and 2.8 per cent responded to fewer than 20 volts.The stimulation with currents of exponential asce