In the hospital ward

Ben was in a hospital ward with two non-Jews. On his first morning, Ben puts on his tefillin, but the non-Jews can’t figure out what he is doing. Finally, one says to the other, “Look how smart those Jews are! He’s taking his own blood pressure.
(Source: The European synagogue Ohel Eliezer, www.theshul.eu – Weekly E-letter, Vol.VI No.11 – Kislev 16, 5773 / November 30, 2012)