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Mike Bullivant: The way this compound works is that it freezes the nerve endings around the sweat ducts so that the sweat ducts can’t actually respond to changes in body temperature. And it also forms a physical barrier because it reacts with the sweat and forms a physical barrier to the sweat duct so the sweat can’t get out, and that’s the way this particular antiperspirant works. So the next thing for me to do is to apply this with a cotton wall ball to the armpit, leave it for a few hours and then check whether it’s sweating or not. And I’ve got a pretty good way of measuring whether it’s effective using a meter.

The way sweating works is really is a biological phenomenon which is quite astonishing. The average body has something like two to three million sweat ducts all over the body and I’ve got twenty to thirty thousand in each armpit, and if all of my sweat glands worked simultaneously, if they all fired at the same time I’d produce about ten litres a day of sweat. But luckily they don’t.

Well I’ve applied antiperspirant to this armpit but not to this armpit and I’m going to use this meter to test whether the antiperspirant’s working and Ellen’s going to give me a hand. Ellen, these two terminals here, if you soak them in that table salt solution so there’s a good contact with my skin and when - if you could just tape the electrodes about two, three inches apart on my skin.

Ellen McCallie: Okay. Would you hold that for me for a second?

Mike: Now in this armpit there is sweat, and the sweat will conduct electricity between the two cotton wool terminals, so we should get a good meter reading.

Ellen: Right there, is that good?

Mike: Yep, that’ll do nicely.

Ellen: Okay.

Mike: Now let’s see if we have a meter reading. The needle, as you can see, has shot right across to the right so there’s good conductivity there, the sweat is conducting the electricity between the two cotton wool pads. And we should get a very different result when we do the same test in the other armpit because there’s no sweat to conduct the electricity between the two cotton wool balls. So let’s try it.

Ellen: Ready?

Mike: Yeah.

Ellen: Sorry Mike.

Mike: You’re so brutal! Now the acid test is have we got a meter reading? See, the needle hasn’t gone quite as far as it did for my right armpit so that does indicate to me that I’m sweating less in this armpit than I am in this armpit, so my antiperspirant is working.