The Host brands Mina's contaminated flesh yet sterilizes Dracula's earth, turning each refuge into a sealed tomb he cannot enter.
Van Helsing uses the Sacred Host as barrier and test. When he touches it to Mina Harker's forehead, the wafer burns her and leaves a livid scar, proving the blood bond has begun a physical spiritual change.
At Carfax and the London lairs, the hunters place a fragment in each box of earth. The consecrated matter sanctifies the native soil and makes the refuge unusable to Count Dracula.
Thin consecrated wafers carried in a white napkin or protective envelopes, broken into fragments and laid within boxes of earth.
The Host simultaneously diagnoses Mina's contamination and neutralizes Dracula's most important material resource.