it is essential that the external stimulus which first
presents itself should be verily the breast and the milk of the
spirit, and then only shall we behold that surprising phenomenon of a
little face concentrated in an intensity of attention.

Behold a child of three years old capable of repeating the same
exercise fifty times in succession; many persons are moving about
beside him; some one is playing the piano; children are singing in
chorus; but nothing distracts the little child from his profound
concentration. Just so does the suckling keep hold of the mother's
breast, uninterrupted by external incidents, and desists only when he
is satisfied.

Only Nature accomplishes such miracles.

If, then, psychical manifestations have their root in Nature, it was
necessary, in order to understand and help Nature, to study it in its
initial periods, those which are the simplest, and the only ones
capable of revealing truths which would serve as guides for the
interpretation of later and more complex manifestations. This, indeed,
many psychologists have done; but, applying the analytical methods of
experimental psychology, they did not start from that point whence the
biological sciences derive their knowledge of life: that is, the
_liberty_ of the living creatures they desire to observe. If Fabre had
not made use of insects, while leaving them free to carry out their
natural manifestations, and observing them without allowing his
presence to interfere in any way with their functions; if he had
caught insects, had taken them into his study, and subjected them to
experiment, he would not have been able to reveal the marvels of
insect life.

If bacteriologists had not instituted, as a method of research, an
environment similar to that which is natural to microbes, both as
regards nutritive substances and conditions of temperature, etc., to
the end that they "might live freely" and thus manifest their
characteristics; if they had confined themselves to fixing the germs
of a disease under the microscope, the science which to-day saves the
lives of innumerable men and protects whole nations from epidemics
would not exist.

Freedom to live is the true basis for every method of observation
applied to living creatures.

_Liberty_ is the experimental condition for studying the phenomena of
the child's attention. It will be enough to remember that the stimuli
of infant attention, being mainly sensory, have a powerful
physiologi