The doctor finally gave up and told her to go home and soak the wound in coal oil twice a day and pray for healing. The remedy worked. As I suspected, a detailed search of the book did not show coal oil as a recommended remedy for any malady. I now believe use of the concoction was for purely psychological reasons.
Prickly heat causes an itchy rash of small red raised red spots with a prickling or stinging sensation. Prickly heat usually affects parts of the body covered by clothes, such as the back, abdomen, neck, upper chest, groin or armpits.
1 Heat rash occurs when the skin's sweat glands are blocked and the sweat produced cannot get to the surface of the skin to evaporate. This causes inflammation that results in a rash.  Common symptoms of heat rash include red bumps on the skin, and a prickly or itchy feeling to the skin (also known as prickly heat).