That did not make every encounter easy.

Traditional healers and western-trained physicians could disagree sharply.

Some patients did not want the treatments Susan recommended.

Others waited too long before calling her.

Still others accepted medicine but resisted changes in sanitation or diet.

Susan could become frustrated.

Her surviving letters and the accounts of people around her reveal a physician who sometimes sounded impatient with what she considered preventable suffering.

That impatience should be read within her workload.

She was not observing public-health problems from an office.

She was seeing them repeatedly in homes.