Since your partner doesn't seem to believe you, maybe he needs a more tangible lesson. Try this: Hook him up to a monitor and get a set of vitals, then hit him with a bat (try to break a rib or two), take his vitals, and get his pain scale, finally wait ten minutes get another set of vitals and...
I know Huntington Hospital in Pasadena, CA is participating in a study comparing the effectiveness of bat venom vs tpa. Here is a link to info on dspa.
http://mblogs.discovermagazine.com/80beats/2011/05/11/anti-stroke-drug-inspired-by-vampire-bats-enter-phase-ii-trials/