They do when you butter them with opsonin. (SIR PATRICK: Gammon.) No: it's not gammon. What it comes to in practice is this. The phagocytes wont eat the microbes unless the microbes are nicely buttered for them. Well, the patient manufactures the butter for himself all right; but my discovery is that the manufacture of that butter, which I call opsonin, goes on in the system by ups and downs--Nature being always rhythmical, you know--and that what the inoculation does is to stimulate the ups or downs, as the case may be. If we had inoculated Jane Marsh when her butter factory was on the up-grade, we should have cured her arm. But we got in on the downgrade and lost her arm for her. I call the up-grade the positive phase and the down-grade the negative phase. Everything depends on your inoculating at the right moment. Inoculate when the patient is in the negative phase and you kill: inoculate when the patient is in the positive phase and you cure.

Ridgeon Monologue from The Doctor's Dilemma

Rehearse Ridgeon's monologue