B. B. No; but why? Why? Because, my dear Sir Patrick, though the germ is there, it's invisible. Nature has given it no danger signal for us. These germs--these bacilli--are translucent bodies, like glass, like water. To make them visible you must stain them. Well, my dear Paddy, do what you will, some of them wont stain. They wont take cochineal: they wont take methylene blue; they wont take gentian violet: they wont take any coloring matter. Consequently, though we know, as scientific men, that they exist, we cannot see them. But can you disprove their existence? Can you conceive the disease existing without them? Can you, for instance, shew me a case of diphtheria without the bacillus? SIR PATRICK. No; but I'll shew you the same bacillus, without the disease, in your own throat. B. B. No, not the same, Sir Patrick. It is an entirely different bacillus; only the two are, unfortunately, so exactly alike that you cannot see the difference. You must understand, my dear Sir Patrick, that every one of these interesting little creatures has an imitator. Just as men imitate each other, germs imitate each other. There is the genuine diphtheria bacillus discovered by Loeffler; and there is the pseudo-bacillus, exactly like it, which you could find, as you say, in my own throat. SIR PATRICK. And how do you tell one from the other? B. B. Well, obviously, if the bacillus is the genuine Loeffler, you have diphtheria; and if it's the pseudobacillus, youre quite well. Nothing simpler. Science is always simple and always profound. It is only the half-truths that are dangerous. Ignorant faddists pick up some superficial information about germs; and they write to the papers and try to discredit science. They dupe and mislead many honest and worthy people. But science has a perfect answer to them on every point. A little learning is a dangerous thing; Drink deep; or taste not the Pierian spring. I mean no disrespect to your generation, Sir Patrick: some of you old stagers did marvels through sheer professional intuition and clinical experience; but when I think of the average men of your day, ignorantly bleeding and cupping and purging, and scattering germs over their patients from their clothes and instruments, and contrast all that with the scientific certainty and simplicity of my treatment of the little prince the other day, I cant help being proud of my own generation: the men who were trained on the germ theory, the veterans of the great struggle over Evolution in the seventies. We may have our faults; but at least we are men of science. That is why I am taking up your treatment, Ridgeon, and pushing it. It's scientific. [He sits down on the chair near the couch]. EMMY [at the door, announcing] Dr Blenkinsop.