Nature has provided an Automatic Food Filter which, if rightly used,
will prevent the introduction of any harmful substance into the stomach.
* * * * *
At the entrance to the throat there are certain muscular folds or
convolutions, including the palate, which, when in repose, form an
organ that is nothing less than a Perfect Food Filter. This filter has
also automatic qualities which compel it to empty itself by the process
we call "Involuntary Swallowing."
Involuntary swallowing is really compulsory swallowing; unless a
voluntary effort to restrain it is set up against it. The real
Swallowing Impulse is so strong that it is practically compelling.
The Food Filter, when rightly performing its protective function, is
impervious to anything except pure water at the right temperature
for admission to the stomach and to nutriment which has been properly
dissolved and chemically converted by salivation (mixture with saliva)
into a substance suitable for further digestion.