The balsam was prepared from spoiled food, of all things, and was an effective agent against the spread of infection in an open wound. It was one of the most undemanding medicines I have ever known, though the drover insisted that it be used sparingly, lest its working be reduced. He said that certain ticks among his herds now spread a rash that no longer yielded to it, and he had no intention of further teaching the imps and demons of sickness about his magic.