and common-place conclusion is
announced that "the ultimate problems of biology are as inscrutable as
of old." All ultimate problems are, I admit, inscrutable. It is, on
the other hand, the business, and has been the glory and triumph, of
science, to examine and solve problems which are scrutable! It is
certainly not the case that, at the present time, discussion is
concentrated on the question of the existence of a vital principle.
There is absolutely no discussion in progress on the subject. No one
even knows or attempts to state what is meant by "a vital principle."
It is a phrase which belongs to "the dead past," when men of science
had not discovered that you get no nearer to understanding a difficult
subject by inventing a name to cover your ignorance. Thirty-five years
ago the word "vitality" was used as some few philosophising writers
are now using the term "vital principle." Huxley at that time attacked
the views of Dr. Lionel Beale, who called in the aid of a mystical
"principle," which he named "vitality," in order to "account for" some
of the remarkable properties of protoplasm. As Huxley pointed out,
this supposed principle "accounted for" nothing, since it was merely a
name for the phenomena for which it was supposed to account. Huxley
pointed out that many chemical compounds have remarkable
properties--as assuredly have the chemical compounds which are present
in protoplasm--but men of science have not found it to help them in
investigating the mechanism of those properties to ascribe them to
mystical intangible "principles" differing from the agencies at work
in other less exceptional substances.

Thus, for instance, water, though a very common and abundant chemical
compound formed by the union of two chemical elements, hydrogen and
oxygen, which, at the temperature and pressure of the earth's surface,
are gaseous, offers many strange properties to our consideration not
shared by other compounds of gaseous elements. For instance, hydrogen,
when it combines with gaseous elements other than oxygen, does not
form a compound which is liquid at the temperature and pressure of the
earth's surface. Its combinations with nitrogen, with chlorine, with
fluorine, and even some with the solid element carbon, are under those
conditions gaseous. What a special character, therefore, has water!
Moreover, water, though a liquid, yet behaves in a most peculiar way
when either cooled below ordinary temperatures or heated a