mount at least, than that of the so-called higher senses. We eat three
times a day; some of us drink oftener; few of us visit the concert hall
or the art gallery as often as we do the dining room. Then, too, these
primitive senses have a stronger influence upon our emotional nature
than those acquired later in the course of evolution. As Kipling puts
it:

Smells are surer than sounds or sights
To make your heart-strings crack.

VI

CELLULOSE

Organic compounds, on which our life and living depend, consist chiefly
of four elements: carbon, hydrogen, oxygen and nitrogen. These compounds
are sometimes hard to analyze, but when once the chemist has ascertained
their constitution he can usually make them out of their elements--if he
wants to. He will not want to do it as a business unless it pays and it
will not pay unless the manufacturing process is cheaper than the
natural process. This depends primarily upon the cost of the crude
materials. What, then, is the market price of these four elements?
Oxygen and nitrogen are free as air, and as we have seen in the second
chapter, their direct combination by the electric spark is possible.
Hydrogen is free in the form of water but expensive to extricate by
means of the electric current. But we need more carbon than anything
else and where shall we get that? Bits of crystallized carbon can be
picked up in South Africa and elsewhere, but those who can afford to buy
them prefer to wear them rather than use them in making synthetic food.
Graphite is rare and hard to melt. We must then have recourse to the
compounds of carbon. The simplest of these, carbon dioxide, exists in
the air but only four parts in ten thousand by volume. To extract the
carbon and get it into combination with the other elements would be a
difficult and expensive process. Here, then, we must call in cheap
labor, the cheapest of all laborers, the plants. Pine trees on the
highlands and cotton plants on the lowlands keep their green traps set
all the day long and with the captured carbon dioxide build up
cellulose. If, then, man wants free carbon he can best get it by
charring wood in a kiln or digging up that which has been charred in
nature's kiln during the Carboniferous Era. But there is no reason why
he should want to go back to elemental carbon when he can have it
already combined with hydrogen in the remains of modern or fossil
vegetation. The synthetic products on which modern chemistry