Some interesting researches have lately been published in an Italian
journal concerning the influence of repose on the sensitiveness of the
retina (a nervous network of the eye) to light and color. The
researches in question--those of Bassevi--appear to corroborate
investigations which were made some years ago by other observers. In
the course of the investigations the subject experimented upon was
made to remain in a dark room for a period varying in extent from
fifteen to twenty minutes. The room was darkened, it is noted, by
means of heavy curtains, through which the light could not penetrate.
After the eyes of the subject had thus been rested in the darkness, it
was noted that the sensitiveness of his sight had been increased
threefold. The mere sense of light itself had increased eighteen
times. It was further noted that the sensitiveness to light rays,
after the eye had been rested, was developed in a special order; the
first color which was recognized being red, then followed yellow,
while green and blue respectively succeeded. If color fatigue was
produced in the eye by a glass of any special hue, it was found that
the color in question came last in the series in point of recognition.
The first of these experiments, regarded from a practical point of
view, would appear to consist in an appreciation of the revivifying
power of darkness as regards the sight. The color purple of the retina
is known to become redeveloped in darkness; and it is probable,
therefore, that the alternation of day and night is a physical and
external condition with which the sight of animals is perfectly in
accord.
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