272 • The Great Plaguein the West, the new“plague.” Old fears merged with new terror. In desper-
ation, European states fell back on existing quarantine mechanisms in hopes
of fending off the new invader. But Europe also searched for transnational
ways to respond to a collective threat and found a vehicle in international
sanitary conferences, beginning at Paris in 1851 , the precursor of the World
Health Organization of today.^18
The officials and scientists meeting at Paris, Constantinople, and Vienna
in the succeeding quarter-century took all infectious diseases as their do-
main, while focusing on cholera, “the classic epidemic disease of the nine-
teenth century.”^19 Between the first and second conferences, an Italian mi-
croscopist and an English anesthetist published pathbreaking works on the
new disease’s mode of transmission. Filippo Pacini traced the illness to an
“organic, living substance of a parasitic nature.” John Snow connected the
outbreak of cholera to drinking water; the clue was a London pump whose
users had become sick. Public health authorities in Europe and the succeed-
ing international conferences, however, failed to follow up these fresh clues
to understanding infectious diseases. As is often the case with scientific rid-
dles, new information on everything from cholera to plague was folded into
the old views of Hodges and Boghurst rather than being gathered into a
fresh theoretical or practical approach. Something was missing.^20
Answers began to emerge on the fringes of the medical communities in
Europe. In 1850 , two obscure investigators, combining microscopic observa-
tion with an ability to draw new conclusions, isolated the anthrax bacillus in
the blood of dying animals and achieved the startling feat of transmitting the
disease to healthy members of the herd!
In the mid- 1850 s a French professor of chemistry, Louis Pasteur, respond-
ing to the plight of a brewer whose beer spoiled during fermentation, stum-
bled unwittingly into this new realm of bacteriology. From the spoilage of
beer and wine, Pasteur’s path led to disease-producing organisms in animals
and humans, including anthrax, chicken cholera, and rabies. In 1885 he pro-
duced a preventive vaccine for rabies, and four years later the Pasteur Insti-
tute at Paris came into being.
Robert Koch, a German country doctor twenty years younger than Pas-
teur, set up a laboratory of sorts in a friend’s garden. In 1876 his findings on
the life cycle of the pathogenic anthrax bacillus were published. Plucked out
of obscurity by medical benefactors, Koch refined the staining techniques
then emerging for identifying bacilli with microscopes far more powerful
than the ones Pepys had read about in 1665. By 1880 Koch was drawing eager