in again. To tell you why it must not would lead me into anatomical
details, not quite in place here as yet: though the day will come, I
trust, when every woman entrusted with the care of children will be
expected to know something about them. But this I may say--Those who
habitually take in fresh breath will probably grow up large, strong,
ruddy, cheerful, active, clear-headed, fit for their work. Those who
habitually take in the breath which has been breathed out by themselves,
or any other living creature, will certainly grow up, if they grow up at
all, small, weak, pale, nervous, depressed, unfit for work, and tempted
continually to resort to stimulants, and become drunkards.

If you want to see how different the breath breathed out is from the
breath taken in, you have only to try a somewhat cruel experiment, but
one which people too often try upon themselves, their children, and their
work-people. If you take any small animal with lungs like your own--a
mouse, for instance--and force it to breathe no air but what you have
breathed already; if you put it in a close box, and while you take in
breath from the outer air, send out your breath through a tube, into that
box, the animal will soon faint; if you go on long with this process, it
will die.

Take a second instance, which I beg to press most seriously on the notice
of mothers, governesses, and nurses: If you allow a child to get into the
habit of sleeping with its head under the bed-clothes, and thereby
breathing its own breath over and over again, that child will assuredly
grow pale, weak, and ill. Medical men have cases on record of scrofula
appearing in children previously healthy, which could only be accounted
for from this habit, and which ceased when the habit stopped. Let me
again entreat your attention to this undoubted fact.