Re: A true touch of insanity?

On Jan 7, 8:03 pm, Wildepad <noreplies> wrote:
> On Mon, 7 Jan 2008 08:38:28 -0800 (PST), IsaacKuo <mech...@[EMAIL PROTECTED]
>
> wrote:

> >On Jan 7, 4:13 am, Wildepad <noreplies> wrote:

> >> The first might be simple, and I'm surprised that more virii
occurring
> >> in nature don't use it -- the sweat glands in the palms (merocrine?)
> >> seem ideal for transfer as the pressure of a handshake could easily
> >> force a virus down the short duct.

> >It's not at all ideal, for what should be obvious reasons.  Skin
> >is anti-germ armor.  If a little pressure was all it took to squeeze
> >germs through, then it wouldn't be doing its job.

> True, but there are chinks in any armor. The function of the sweat
> glands must outweigh other considerations, but they are still an
> opening, and openings can be exploited.

Since diseases don't seem to exploit hand sweat glands
much, but they do exploit the hand->mouth opening a lot, it
would seem that the latter is the more practical opening to
exploit.

But if we just look at the physics of things, why should the
pressure of a handshake be sufficient to push fluid down a
sweat duct?  It doesn't seem plausible to me due to the
narrow diameter of the duct--but I'm not sure how to go
about calculating how far fluid would be pushed.

To a first approximation, I think fluid wouldn't be pushed
into the sweat gland at all.  You can consider the flesh cells
to be flexible membranes around incompressible fluid, and
the sweat fluid to be incompressible also.  External pressure
would result in a pressure gradient, but no local pressure
points preferring to push the sweat inward.

Isaac Kuo