The reaction to bitter, which requires twice as long in the above case as that of any other quality, was considerably shorter when the stimulus was applied to the root of the tongue. This suggests that the differences found by Kiesow may in part, at least, depend on the accessibility and perhaps also on the number of such various types of taste buds as there may be. Taking these reactions times as they stand, the average time for the four taste qualities may be said to be about one-half a second. As compared with the reaction times of other sense modes, taste is more sluggish than any other sense, with the possible exception of smell. Averaging the results of numerous observers for the range of stimulus qualities and intensities that have been employed, the comparative times are somewhat as follows: Reaction to Second ─────────────────────── sound .146 touch .149 sight .189 (?) smell .500 (?) It should, of course, be borne in mind that these are but averages of figures which vary considerably with a large number of factors, although it is true that the influence of these factors can itself be subjected to precise measurement. _Determinants of Reaction Time to Taste_ By way of illustration of the numerous incidental and extraneous factors that influence reaction time to the taste qualities we may instance the temperature of the solution. In what seems to have been a carefully conducted series of observations Chinaglea has recently shown the nature of this influence. As Kiesow had already found, the temperature of the solution (within the pain limits) does not influence the intensity of stimulus required to produce the weakest sensation, and hence does not modify the threshold or limen. But such changes Chinaglea showed to have a measurable influence on the reaction time to taste stimuli. Lowering the temperature of the solution below that of the mouth does not affect reaction time to salt, but it lengthens the time for the other qualities. Raising the temperature of the solution above that of the mouth quickens the reaction to sweet, but lengthens the reaction to bitter and sour. ------------------------------------------------------------------------ CHAPTER V THE SENSE ORGAN OF TASTE _Comparison With Other Sense Organs_