[rivo]

What would be the proper punctuation if you rearranged the sentence slightly?

Dr Johnson kicked a large rock and said, “I refute it thus.”, as his foot rebounded.

Is the period redundant? Or the comma after it? None of them? This looks almost as ugly as two periods.

[mdp2021]

The period before the quotation mark is redundant, because the quotation mark implies it (in this case).

[a9h74j]

To me it looks wrong to omit a period in a famous short one-sentence statement. To stay within American style, I would rearrange the sentence to end with the quote, "I refute it thus."