Example of metaphor used in Pygmalion by George Bernard Shaw?

One example of metaphor can be found in the quote below;

And so I shall! If the Higgins oxygen burns up her little lungs, let her seek some stuffiness that suits her. She's an owl sickened by a few days of my sunshine. Very well, let her go, I can do without her. I can do without anyone. I have my own soul! My own spark of divine fire!