uch as crowd
the normal school in Philadelphia, this sort of tension and this
variety of study occasion an amount of ill-health which is sadly
familiar to many physicians."[34]

Experience teaches that a healthy and growing boy may spend six hours
of force daily upon his studies, and leave sufficient margin for
physical growth. A girl cannot spend more than four, or, in
occasional instances, five hours of force daily upon her studies, and
leave sufficient margin for the general physical growth that she must
make in common with a boy, and also for constructing a reproductive
apparatus. If she puts as much force into her brain education as a
boy, the brain or the special apparatus will suffer. Appropriate
education and appropriate co-education must adjust their methods and
regimen to this law.

Another detail is, that, during every fourth week, there should be a
remission, and sometimes an intermission, of both study and exercise.
Some individuals require, at that time, a complete intermission from
mental and physical effort for a single day; others for two or three
days; others require only a remission, and can do half work safely for
two or three days, and their usual work after that. The diminished
labor, which shall give Nature an opportunity to accomplish her
special periodical task and growth, is a physiological necessity for
all, however robust they may seem to be. The apportionment of study
and exercise to individual needs cannot be decided by general rules,
nor can the decision of it be safely left to the pupil's caprice or
ambition. Each case must be decided upon its own merits. The
organization of studies and instruction must be flexible enough to
admit of the periodical and temporary absence of each pupil, without
loss of rank, or necessity of making up work, from recitation, and
exercise of all sorts. The periodical type of woman's way of work must
be harmonized with the persistent type of man's way of work in any
successful plan of co-education.

The keen eye and rapid hand of gain, of what Jouffroy calls
self-interest well understood, is sometimes quicker than the brain and
will of philanthropy to discern and inaugurate reform. An illustration
of this statement, and a practical recognition of the physiological
method of woman's work, lately came under my observation. There is an
establishment in Boston, owned and carried on by a man, in which ten
or a dozen girls are constantly employed. Each of them is