Differences in _intensity_ of sensation are familiar to every person who

prefers two lumps of sugar rather than one lump in his coffee; the sweet
is of the same quality in either case, but differs in intensity
Differences in _intensity_ of sensation are familiar to every person who
prefers two lumps of sugar rather than one lump in his coffee; the sweet
is of the same quality in either case, but differs in intensity. In
every field of sensation, the intensity may proceed from the smallest
amount to the greatest amount discernible. In general, the intensity of
the sensation depends on the intensity of the stimulus, though the
condition of the sense-organ as regards fatigue or adaptation to the
stimulus has its effect. It is obvious that a stimulus may be too weak
to produce any sensation; as, for example, a few grains of sugar in a
cup of coffee or a few drops of lemon in a quart of water could not be
detected. It is also true that the intensity of the stimulus may be so
great that an increase in intensity produces no effect on the sensation;
as, for example, the addition of sugar to a solution of saccharine would
not noticeably increase its sweetness. The lowest and highest intensity
points of sensation are called the lower and upper _limen_, or
threshold, respectively.