damp and dirty places; underfed people are more prone to illness than
others, and so are those who are overtired. Therefore illness and
early death must be the heritage of the poor who, underfed and
overtired, live in damp and dirty places? No. It is a question of
vehicles. Microbes spread in all directions from the sources of
infection, by means of dust, insects and all the usual objects of
life, in fact by all the means of transport. They exist in
inconceivable and fabulous numbers; and every sick person is an almost
incredible source of illness and death. One single person would
suffice to contaminate the whole of Europe.

The means of transport allow microbes to cross oceans and continents
in every sense. We need only observe the transatlantic lines, and
those of the railways of the world, in order to realize the lines of
communication between the maladies which afflict humanity in all the
places of the earth. We need only study the industrial changes of
matter in order to follow in detail the daily path of the microbes,
which put all classes of society into intimate communication. The rich
lady wears linen on her person which comes from the hands of the poor,
and is constantly in their keeping; she cannot put food into her mouth
unless it is offered to her by the poor who have handled it over and
over again.

The air which is breathed by the rich may contain in its dust the
desiccated germs which a consumptive workman has scattered on the
ground. There is no way of escape. Statistics prove this: the death
rate from infectious diseases is tremendously high in all countries,
among both rich and poor, although the poor die in a double proportion
to the rich. How can we deliver ourselves from this scourge? Only on
condition that there be no more sources of infection, that is to say,
that there be no longer unhealthful places in the world, and no
underfed people constrained to work beyond their strength. The only
way by which the individual may escape is that by which all humanity
may be saved. This is a great principle, which seems to ring like a
trumpet call: Men, help one another, or you will die.

It is a fact that science has inaugurated "works of sanitation" as its
practical contribution to the fight against mortality; towns have been
opened out, water has been laid on, houses have been built for the
poor, and labor has been protected. All the environment tends to
ameliorate the "conditions of life" of the po