t is not too much to say that the modern colonization
of the tropics and subtropics by Northern races, which is one of the
greatest and most significant triumphs of our civilization, would have
been almost impossible without it. Its advance depended upon two
powders, one white and the other black,--quinine and gunpowder.

For nearly three centuries we rested content with the knowledge that in
quinine we had a remedy for malaria, which, if administered at the
proper time and in adequate doses, would break up and cure ninety per
cent of all cases. Just how it did it we were utterly in the dark, and
many were the speculations that were indulged in. It was not until
1880, that Laveran, a French army surgeon stationed in Algeria,
announced the discovery in the blood of malarial patients of an organism
which at first bore his name, the _Hematozoon-Laveran_, now known as the
_Plasmodium malariae_. This organism, of all curious places, burrowed
into and found a home in the little red corpuscles of the blood. At
periods of forty-eight hours it ripened a crop of spores, and would
burst out of the corpuscles, scattering throughout the blood and the
tissues of the body, and producing the famous paroxysm. This accounted
for the most curious and well-marked feature of the disease, namely, its
intermittent character, chill and fever one day, and then a day of
comparative health, followed by another chill day and so on, as long as
the infection continued. One problem, however, was left open, and that
was why certain forms of the disease had their chills every fourth day
and so were called _quartan_ ague. This was quickly solved by the
discovery of another form of the organism, which ripened its spores in
three days instead of two. So the whole curious rhythm of the disease
was established by the rate of breeding or ripening of the spores of the
organism. Later still another form was discovered, which had no such
regular period of incubation and gave rise to the so-called irregular,
or _autumnal_, malarial fevers. That form of the fever which had a
paroxysm every day, the classic _quotidian_ ague, remained a puzzle for
a little longer, but was finally discovered to be due chiefly to the
presence of two broods, or infections, of the organism, which ripened
on alternate days and hence kept the entire time of the unfortunate
patient occupied.

The mystery of the remedial effect of quinine was also solved, as it was
found that, if administ