soldiers encamped in ruined cities, reeking with the dirt and poison
of centuries; of--but it is not my place to find fault; all I will
say is, that the wise and humane officer, when once his eyes are
opened to the practical value of physical science, will surely try
to acquaint himself somewhat with those laws of drainage and of
climate, geological, meteorological, chemical, which influence,
often with terrible suddenness and fury, the health of whole armies.
He will not find it beyond his province to ascertain the amount and
period of rainfalls, the maxima of heat and of cold which his troops
may have to endure, and many another point on which their health and
efficiency--nay, their very life may depend, but which are now too
exclusively delegated to the doctor, to whose province they do not
really belong. For cure, I take the liberty of believing, is the
duty of the medical officer; prevention, that of the military.

Thus much I can say just now--and there is much more to be said--on
the practical uses of the study of Natural History. But let me
remind you, on the other side, if Natural History will help you, you
in return can help her; and would, I doubt not, help her and help
scientific men at home, if once you looked fairly and steadily at
the immense importance of Natural History--of the knowledge of the
"face of the earth." I believe that all will one day feel, more or
less, that to know the earth ON which we live, and the laws of it BY
which we live, is a sacred duty to ourselves, to our children after
us, and to all whom we may have to command and to influence; ay, and
a duty to God likewise. For is it not a duty of common reverence
and faith towards Him, if He has put us into a beautiful and
wonderful place, and given us faculties by which we can see, and
enjoy, and use that place--is it not a duty of reverence and faith
towards Him to use these faculties, and to learn the lessons which