THE PRESIDENTIAL ADDRESS.
17
It is not alone a most fascinating study, throwing a flood of light
on most obscure problems of vegetable physiology, but it is also
of immense practical importance in the manuring of crops. It is,
at least, possible that the mere unintelligent application of the
constituents needed for plant life may in some cases do more
harm than good by discouraging the efforts of these invaluable
living auxiliaries.
As we get higher in the scale of life, the influence of lower
forms becomes of even greater importance. In medicine,
instead of being able, as we seemed to have the prospect of being,
to regard the body a highly-developed chemical laboratory, the
processes of which were more or less analogous to those known
in the work-shop of the chemist, we find that health or sickness,
life or death, depend to an undetermined degree on the life-
history of micro-organisms, the very existence of which we did
not guess a few years ago ; it is the culture in the flask of the
bacteriologist rather than the re-action in the test-tube of the
chemist that tells the secret of disease and its cure. It is the
foes within the human frame far more than the foes without that
imperil it.
Time would fail to follow out the ramifications of this wide
question. I will but remark on the fact that while we are thus
constantly meeting fresh proofs of the all-prevailing influence of
living organisms, we seem as far off as ever from learning what
life is. It certainly is not organic in the sense of depending on
the presence of organization ; it is the living "protoplasm" that
makes the organization, not the organization that makes the
life, but how to express in terms that we can comprehend what
is the real difference between living and dead matter is a problem
as obscure as ever.
We do but learn the more we know how little we know and
realize how much there is to learn, how much more to believe.