Although we have no record of how he managed his dyspepsia, the standard treatment in the 1840s was carbonated alkali, which would have neutralized the gastric acid that otherwise kills harmful bacteria. In the absence of the gastric acid barrier, gastroenteritis can be caused by as few as one ten-thousandth the number of bacteria usually needed.

In 1841 there was no effective treatment for enteric fever. The most a doctor could do was adhere steadfastly to medicine’s most sacred tenet, primum non nocere — first do no harm.

At least Miller did not bleed the president. But he gave him a host of toxic medications that were then considered the standard of care — including opium, which retards the intestine’s ability to rid itself of microbial pathogens, facilitating their invasion into the bloodstream.

Enemas, which Miller repeatedly gave to Harrison, are also potentially dangerous in such patients. They can perforate ulcers produced by S. typhi and S. paratyphi in the ileum, the lower end of the small intestine, through which the bacteria would be able to escape from the intestine into the bloodstream, resulting in sepsis.