I concur with shimonv (like the new pic!) but will add that I personally might balk at the amount of "good faith" behind the same email sent out three days in a row (or hours or minutes).
If your goal is to get additional information, rather than simply to comply as quick and as easily as possible, I would worry less about how many days between attempts and more about the medium(s) used. I would not send three emails myself, but would make at least one of the attempts by phone. Moreover, if I had more than one number (e.g., the doctor's office and his department head's), I would try more than one. Sending three emails strikes me as putting Einstein's definition of insanity into practice.