An example of metaphor drawing upon scientific concepts,
"The singer places the patient on the painting [sand painting of the Holy People], touching the feet, hands, knees, shoulders, breast, back, and head of the divine figures and then the corresponding parts of the patient, performing thus what is essentially a bodily identification of the human and the divine. This is the climax of the sing: the whole curing process may be likened, Reichard says, to a spiritual osmosis in which the illness in man and the power of the deity penetrate the ceremonial membrane in both directions, the former being neutralised by the latter."
Clifford Geertz (2000) Religion as a cultural system (first published 1966), in The Interpretation of Cultures. Selected Essays. 2nd Edition. New York. Basic Books
The reference to osmosis in relation to a membrane may be seen as an example extended metaphor.