the ratio of the atmospheric condensation. By physiological limits we
mean simply that there is a degree of atmospheric condensation beyond
which we cannot go without jeopardizing the well-being of the subject.

(_To be continued_.)

* * * * *

EYESIGHT: ITS CARE DURING INFANCY AND YOUTH.[1]

[Footnote 1: A lecture delivered before the Franklin Institute,
December 5, 1890.--_From the Journal of the Institute_.]

By L. WEBSTER FOX, M.D.

Medical science, as taught in our medical colleges to-day, has two
objects in view: (1) the prevention of disease; (2) the amelioration
of disease and its cure. Some of our advanced thinkers are suggesting
a new mode of practice, that is the prevention of disease by proper
hygienic measures. Chairs are being established and professors
appointed to deliver lectures on hygiene. Of what value is the
application of therapeutics if the human economy is so lowered in its
vital forces that dissolution is inevitable? Is it not better to
prevent disease than to try the cure after it has become established,
or has honeycombed the constitution?

These few preliminary remarks are _apropos_ to what is to follow in
the subject which I have selected as the topic for discussion this
evening.

Vision is the most useful of all the senses. It is the one gift which
we should cherish and guard the most. And at no time in one's life is
it more precious than in infancy and youth.

In infancy, when the child is developing, the one great avenue to the
unfolding, or more properly speaking, the development, of the
intellect is through the eye. The eye at this period holds in abeyance
all the other senses. The child, when insensible to touch, taste,
smell or hearing, will become aroused to action by a bright light or
bright colors, or the movement of any illuminated object, proving to
all that light is essential to the development of the first and most
important sense. Again, the infant of but six days of age will
recognize a candle flame, while its second sense and second in
importance to its development--hearing--will not be recognized for
_six_ weeks to two months. Taste, touch and smell follow in regular
sequence. Inasmuch as light makes thus early an impression on the
delicate organ of vision, how necessary it behooves us to guard the
infant from too bright lights or too much exposure in our bright
climate. Mothers--not only the young mother with her first ch