There’s a particular kind of silence in a barn at 6 a.m. You’re already awake, your coffee’s gone cold, and you’re staring at two bottles you were about to mix. I almost did it. Penicillin in one hand, a vitamin C shot in the other, because some textbook said “broad-spectrum coverage, hit it from both sides.” That line has probably caused more animal deaths than I care to count. I pulled back. Something my old mentor hammered into me surfaced, half-remembered, about acid and base. I mixed a tiny bit in a spare cup instead. Within minutes it went cloudy, then threw a fine white sludge at the bottom. That…