They do not move--_they have to be carried_. More than this, like
all other disease-germs, while incredibly tiny and infinitesimal, they
have a definite weight of their own, and are subject to the law of
gravity. They do not flit about hither and thither in the atmosphere,
thistledown fashion, but rapidly fall to the floor of whatever room or
receptacle they may be thrown in. And the problem of their transference
is not that of direct carrying from one victim to the next, but the
intermediate one of infected materials, such as are usually associated
with visible dust or dirt. In short, keep dust or dirt from the floor,
out of our food, away from our fingers or clothing or anything that can
be brought to or near the mouth, and you will practically have abolished
the possibility of the transference of tuberculosis. The consumptive
himself is not a direct source of danger. It is only his filthy or
unsanitary surroundings. Put a consumptive, who is careful of his sputum
and cleanly in his habits, in a well-lighted, well-ventilated room, or,
better still, out of doors, and there will be exceedingly little danger
of any other member of his family or of those in the house with him
contracting the disease. Wherever there is dirt or dust there is danger,
and there almost only. Thorough and effective house-reform--not merely
in tenements, alas! but in myriads of private houses as well--would
abolish two-thirds of the spread of tuberculosis.

It is not necessary to isolate every consumptive in order to stop the
spread of the disease. All that is requisite is to prevent the bacilli
in his sputum from reaching the floor or the walls, to have both the
latter well lighted and aired, and, if possible, exposed to direct
sunlight at some time during the day, and to see that dust from the
floor is not raised in clouds by dry sweeping so as to be inhaled into
the lungs or settle upon food, fingers, or clothing, and that children
be not allowed to play upon such floors as may be even possibly
contaminated. These precautions, combined with the five-to-one resisting
power of the healthy human organism, will render the risk of
transmission of the disease an exceedingly small one. To what
infinitesimal proportions this risk can be reduced by intelligent and
strict sanitation is illustrated by the fact, already alluded to, of the
almost complete germ-freeness of the dust from walls and floors of
sanitorium cottages, and by the even more convincin