President Garfield: From Radical to Unifier by C. W. Goodyear:
Garfield’s were only beginning. His right arm stung; in his back throbbed a deeper ache; his feet prickled with electric, nervous pain. But, not five minutes after the shooting, worse discomfort started coming from an outside source: his doctors. The first to arrive poured brandy and ammonia salts down the president’s throat, then turned him over for what established practice deemed a necessity. Flicking aside a clot on the small of the patient’s back, the physician sank a finger into the gunshot wound to try tracing the path of the slug still within.
As new medics reached the depot, each insisted on repeating the torture. Grimy digits, attached to men who did not yet believe in washing their hands, tunneled past shattered ribs to burrow into the president. Metal probes followed, but got hooked on bone shards at a depth of three inches. Pushing down on Garfield’s sternum was necessary to free these instruments. Coating them, imperceptible to the naked eye (and fictional, to many of those in the American medical community) were millions of living microbial poisons, now seeded across the president’s abdomen.