e oil and a handful
of maccaroni; the Chinese exist almost entirely on rice, and the Arabs
will live for weeks on dried dates. The surprise is not so much that
these people exist, but that they are healthy and strong. Travelers
again and again have noted that the Turkish porters in Constantinople
will carry a burden that two strong Americans can hardly lift, and that
coolies can tire a horse in running with the jinrikisha in China or
Japan.

Doubtless most of this abstemiousness is due to poverty, since all
nationalities soon fall into our ways of eating when they come to these
shores, but their sparingness is none the less a proof that much of what
we eat is an unnecessary burden to our stomachs. The primary purpose of
eating is to sustain life, not to please the palate. We need material to
replenish the waste of tissue, material to make blood and bone and
flesh, and that is all.

Out of a pound of meat, not more than one tenth is of any value, and the
same proportion holds good with many other articles of food. Now, it is
evident that if some method existed by which the nutritious elements
could be extracted and concentrated, the process of eating would be
greatly simplified, and much to our advantage.

The first effort in this line was made thirty years ago in the shape of
condensed milk, and the inventor was heartily laughed at. He lived,
however, long enough to laugh at other people, and died worth seven
millions of dollars. Now the condensing of milk has grown to be a very
large industry.

The processes employed are very simple, the fresh milk being put into a
great copper tank with a steam jacket. While it is being heated sugar is
added, and the mixture is then drawn off into a vacuum tank, where
evaporation is produced by heat.

The vacuum tank will hold, perhaps, nine thousand quarts. It has a glass
window at the top, through which the operator in charge looks from time
to time. He can tell by the appearance of the milk when the time has
arrived to shut off the steam, and this must be done at just the right
moment, else the batch will be spoiled.

Next the condensed milk is drawn into forty-quart cans, which are set in
very cold spring water, where they are made to revolve rapidly by a
mechanical contrivance in order that their contents may cool evenly.

When the water does not happen to be cold enough, ice is put in to bring
it down to the proper temperature. Finally the tin cans of market size
are fi