type of bacteria he had seen the year before. Jacob Henle’s dream had been
that “It could be empirically proven that [bacteria] are actually the active
part (the cause of the disease) if one could isolate the contagious organism
and the contagious fluid and observe the powers ...”^35 reverberating in his
ears, Koch had a spark of inspiration.
Walking out of his makeshift laboratory and exiting the rear doors, he
entered his garden and pulled a healthy rabbit out of its cage. Controlling
for normal, Koch sliced the rabbit’s ear, drawing a crimson trickle, and
verified microscopically that the rabbit’s blood was free of bacteria. He
then injected the dead animal’s animalcule-laden blood into the fit rabbit’s
ear. Bacterial life cycles were completely unknown at the time—there
wasn’t even agreement that germs were real, let alone an appreciation of
their mode of operation and lethality. Retiring to bed that night, Koch had
no idea what the next day (Christmas Eve) would bring.
I believe, given Koch’s singlemindedness and obsessive focus, he had
trouble getting to sleep that night. He faced a full clinic on the twenty-
fourth, tending to his patients in his upstairs exam room overlooking the
backyard (where the rabbit was caged). He worked from morning to night.
When his work was done he checked on his leporid patient.
The rabbit was dead.
Bringing the rabbit inside, Koch sampled the blood and found the same
bacteria he had seen the day before. Recording in his journal, he described
the selfsame bacteria in “moderate numbers” in his research notebook.
That Christmas Eve, Koch retired to bed, as expectant as any child,
planning his next move. Instead of disposing of the dead rabbit’s body, he
saved it for more experimentation the next day.
Christmas morning, Koch sampled more tissue from the dead animal,
no doubt starting to reek. (This was the 1870s, before the invention of
electricity, light bulbs, and refrigerators.) Even more bacteria were
growing, and Koch was becoming more convinced that these multiplying
organisms were the cause of anthrax. Not just recording his observations
in his notebooks, Koch began planning experiments to verify his
hypothesis that these plain little microscopic bodies were the culprits of
the primeval scourge.
Koch was able to pass on the disease from the rabbit to additional pet
animals from their household, including pet mice. Each animal perished
from anthrax, and each specimen showed the telltale bacteria under his