d of twenty per cent. of glycerin by
fermenting black strap molasses or other syrup with California wine
yeast. During the fermentation it is necessary to neutralize the acetic
acid formed with sodium or calcium carbonate. It was estimated that
glycerin could be made from waste sugars at about a quarter of its
war-time cost, but it is doubtful whether the process would be
profitable at normal prices.

We can, if we like, dispense with either yeast or bacteria in the
production of glycerin. Glucose syrup suspended in oil under steam
pressure with finely divided nickel as a catalyst and treated with
nascent hydrogen will take up the hydrogen and be converted into
glycerin. But the yield is poor and the process expensive.

Food serves substantially the same purpose in the body as fuel in the
engine. It provides the energy for work. The carbohydrates, that is the
sugars, starches and celluloses, can all be used as fuels and can
all--even, as we have seen, the cellulose--be used as foods. The final
products, water and carbon dioxide, are in both cases the same and
necessarily therefore the amount of energy produced is the same in the
body as in the engine. Corn is a good example of the equivalence of the
two sources of energy. There are few better foods and no better fuels. I
can remember the good old days in Kansas when we had corn to burn. It
was both an economy and a luxury, for--at ten cents a bushel--it was
cheaper than coal or wood and preferable to either at any price. The
long yellow ears, each wrapped in its own kindling, could be handled
without crocking the fingers. Each kernel as it crackled sent out a
blazing jet of oil and the cobs left a fine bed of coals for the corn
popper to be shaken over. Driftwood and the pyrotechnic fuel they make
now by soaking sticks in strontium and copper salts cannot compare with
the old-fashioned corn-fed fire in beauty and the power of evoking
visions. Doubtless such luxury would be condemned as wicked nowadays,
but those who have known the calorific value of corn would find it hard
to abandon it altogether, and I fancy that the Western farmer's wife,
when she has an extra batch of baking to do, will still steal a few ears
from the crib.

XI

SOLIDIFIED SUNSHINE

All life and all that life accomplishes depend upon the supply of solar
energy stored in the form of food. The chief sources of this vital
energy are the fats and the sugars. The former contain two and a qu