The lower nitrates, known as pyroxylin, are less explosive, although
still very inflammable. All these nitrates are, like the original
cellulose, insoluble in water, but unlike the original cellulose,
soluble in a mixture of ether and alcohol. The solution is called
collodion and is now in common use to spread a new skin over a wound.
The great war might be traced back to Nobel's cut finger. Alfred Nobel
was a Swedish chemist--and a pacifist. One day while working in the
laboratory he cut his finger, as chemists are apt to do, and, again as
chemists are apt to do, he dissolved some guncotton in ether-alcohol and
swabbed it on the wound. At this point, however, his conduct diverges
from the ordinary, for instead of standing idle, impatiently waving his
hand in the air to dry the film as most people, including chemists, are
apt to do, he put his mind on it and it occurred to him that this sticky
stuff, slowly hardening to an elastic mass, might be just the thing he
was hunting as an absorbent and solidifier of nitroglycerin. So instead
of throwing away the extra collodion that he had made he mixed it with
nitroglycerin and found that it set to a jelly. The "blasting gelatin"
thus discovered proved to be so insensitive to shock that it could be
safely transported or fired from a cannon. This was the first of the
high explosives that have been the chief factor in modern warfare.

But on the whole, collodion has healed more wounds than it has caused
besides being of infinite service to mankind otherwise. It has made
modern photography possible, for the film we use in the camera and
moving picture projector consists of a gelatin coating on a pyroxylin
backing. If collodion is forced through fine glass tubes instead of
through a slit, it comes out a thread instead of a film. If the
collodion jet is run into a vat of cold water the ether and alcohol
dissolve; if it is run into a chamber of warm air they evaporate. The
thread of nitrated cellulose may be rendered less inflammable by taking