g fermentation and putrefaction which have been
applied with great economic advantage to the preservation of food were
many of them developed in the course of the study of the infectious
diseases. Whether the development of the present civilization is for
the ultimate advantage of man may perhaps be disputed, but medicine
has made it possible.

The infectious diseases appearing in the form of great epidemics have
been important factors in determining historical events, for they have
led to the defeat of armies, the fall of cities and of nations. War is
properly regarded as one of the greatest evils that can afflict a
nation, since it destroys men in the bloom of youth, at the age of
greatest service, and brings sorrow and care and poverty to many. But
the most potent factor in the losses of war is not the deaths in
battle but the deaths from disease. If we designate the lives lost in
battle, the killed and the wounded who die, as 1, the loss of the
German army from disease in 1870-71 was 1.5, that of the Russians in
1877-78 was 2.7, that of the French in Mexico was 2.8, that of the
French in the Crimea 3.7, that of the English in Egypt 4.2. The total
loss of the German army in 1870-71 from wounds and disease was 43,182
officers and men, and this seems a small number compared with the
129,128 deaths from smallpox in the same period in Prussia alone. In
the Spanish American war there were 20,178 cases of typhoid fever with
1,580 deaths. In the South African war there were in the British
troops 31,118 cases of typhoid with 5,877 deaths, and 5,149 deaths
from other diseases while the loss in battle was 7,582. The Athenian
plague which prevailed during the Peloponnesian war, 431-405 B.C., not
only caused the death of Pericles, but according to Thucydides a loss
of 4,800 Athenian soldiers, and brought about the downfall of the
Athenian hegemony in Greece. In the Crimean war between 1853-56,
16,000 English, 80,000 French and 800,000 Russians died of typhus
fever. The plague contributed as much as did the arms of the Turks to
the downfall of Constantinople and the Eastern Empire in 1453. It was
the plague which in 1348 overthrew Siena from her proud position as
one of the first of the Italian cities and the rival of Florence, and
broke the city forever, leaving it as a phantom of its former glory
and prosperity. The work on the great cathedral which had progressed
for ten years was suspended, and when it was resumed it was upon