impeded
by the presentment of isolated educational facts in a desultory
manner, because it is impossible to disconnect things united by a
sacred and eternal law.

* * * * *

In the above "model" lesson, it is claimed that only two perceptions
are dealt with, those of cold and heat, and that the child has been
allowed a good deal of liberty, but of a judicious kind.

Now it would be exceedingly difficult to limit the perceptions
strictly to two, especially when dealing with persons placed in an
environment abounding in stimuli, who have already stored up a whole
chaos of images. But such being the object in view, it is necessary to
eliminate as far as possible all other perceptions, to arrest those
two, and so to polarize attention on them that all other images shall
be obscured in the field of consciousness. This would be the
scientific method tending to isolate perceptions; and it is in fact
the practical method adopted by us in our education of the senses. In
the case of cold and heat, the child is "prepared" by the isolation of
the particular sense in question; he is placed blindfolded in a silent
place, to the end that thermic stimuli alone may reach him. In front
of the child are placed two objects perfectly identical in all
characteristics perceptible to the muscular tactile sense: of the same
dimensions, the same shape, the same degree of smoothness, the same
resistance to pressure; for instance, two india-rubber bags, filled
with the same quantity of water, and perfectly dry on the outside. The
sole difference is the temperature of the water in the two bags; in
the hot one, the water would be at a temperature of sixty degrees
centigrade; in the cold, at ten degrees centigrade. After directing
the child's attention to the object, his hand is drawn over the hot
bag, and then over the cold one; while his hand is on the hot bag the
teacher says: It is hot! While he feels the cold one he is told: It
is cold. And the lesson is finished. It has consisted merely of two
words, and of a long preparation designed to ensure that as far as
possible, the two sensations corresponding to these two words shall be
the only ones that reach the child. The other senses, sight and
hearing, were protected against stimuli; and there was no perceptible
difference in the objects offered to the touch save that of
temperature. Thus it becomes approximately probable that the child
will achieve the perception of two sens