I WAS sitting in the shade of a pomegranate tree in a remote valley in southern Afghanistan when I heard the pop. The sun was just coming up, and I could see a thin plume of smoke ascending from a nearby hilltop. The screams were shrill and full of fear.

By the time I reached the top of the hill, the screaming had stopped. A soldier appeared, his hands covered in blood. He looked stunned. On the other side of a small ridge, there was a shallow crater, and in the middle of it was my friend Eddie. All that remained of his right leg was several inches of shredded flesh and bone. “Doc,” he said. “Help.” My hands trembled as I unzipped my aid bag. I had done this once before. On a goat.

For years, People for the Ethical Treatment of Animals has spearheaded a campaign to end the military’s practice of using live animals to train medics. That effort gained traction in June when 71 members of Congress signed a letter urging the Defense Department to phase out the program. One of the sponsors was Representative Joe Heck, Republican of Nevada, who, as an Army Reserve doctor, served in a hospital west of Baghdad in 2008. His sponsorship, along with the signatures of nine other veterans, gives the impression that even the military finds “live tissue” training cruel and unnecessary. Their proposed solution: “high-tech, cost-effective simulation.”

Is it cruel to cut, slice and stab an animal to death while it’s under anesthesia? Absolutely. Is it unnecessary? It depends. The letter points to a recent military study that concluded that “there is no objective benefit of animal training” as compared with high-tech simulators. But that study was conducted in a laboratory and the participants weren’t combat medics preparing to deploy to a war zone. They were airmen assigned to a medical center in Mississippi. So, yes, in that case, it was not necessary. But in my case, as someone who’d soon be responsible for the lives of 30 men operating in Kandahar, it was.