184 THE DISCOVERY OF THE CHILD
voice and after that till they could speak—thus curing a large
number of mutes.
Another principle of sensorial education is that of distinguish-
ing differences between stimuli.
That includes as teaching preparation a classification of the
different groups of sensations, and then the grading of every group
which lends itself to it practically.
We can first of all distinguish between noises and sounds,
beginning with strongly contrasting differences and passing on to
almost imperceptible differences. Then we proceed to the different
qualities of sound which have different origin, e.g., the human
voice and instruments; and finally we deal with the scale of musical
To siim up and emphasize the fundamental groupings, we
will indicate the four classes of auditory sensations—silence, the
speaking human voice, noises, music.
The lesson on silence are separate, independent exercises which
have an important practical effect on discipline.
The analysis of sounds relative to speech are exercises con-
nected with the learning of the alphabet.
For studying noises, there is in our present system illustrative
material of quite simple and primitive character consisting of
a set of wooden (or cardboard) boxes, made in identical pairs, and
prepared in such a way that, when in series, they produce graduated
noises. As with the other sense-materials, the method of using
the boxes for noises is to mix them all together and then arrange
in pairs those boxes which give out the same noises. Then, trying
to estimate the difference among the boxes in one series, the
children use the evidence to place the things in graduated
For the education of the musical sense, there was adopted a
series of bells which. Signorina Anna Maccheroni had prepared
with great accuracy. The bells, each mounted on a stand and
separate from each other, constitute a group of objects identical
m appearance, but which, when struck with a little hammer,