I'm sorry it's taken me so long to reply to this, but it's finals
week here and the students are keeping me hopping!
        I wanted to address Lisa Marasco's concerns about the ratio of
stomach acid to milk in the stomach, and whether or not this recipe is an
realistic representation of what actually occurs in the stomach.  The pH of
vinegar is about 3 and the pH of the gastric juices in the stomach is about
0.9.  This means that stomach acid (or the hydrogen ion concentration) is
more than 100 times as concentrated than the vinegar used.  If you had
actual gastric juice, you would add about a third of a teaspoon to the milk
to get the same effect.  To get the same amount of hydrogen ions from the
vinegar, you need to add 2/3 of a cup.  Although the volumes are very
different, the amount of "acid" (hydrogen ions) you are adding is the same.
I hope this explanation helps.

Donna

>>>OK, the "recipe" for the "Science Fair" test tubes comparing digestion of
>breastmilk, formula and cows milk is: 2/3 white vinegar and 1/3 milk.  You
>can try different ratios and see what happens.<<
>I heard about this wonderful example a few years ago, but also wondered about
>the "recipe".  I would want to approximate what happens when milk hits the
>stomach, and it doesn't seem to me that there is more acid in the stomach
>than milk in such a ratio!  Does anyone have more specific knowledge that can
>address this? Does the ratio used for this illustration matter, or is it only
>the principle that matters?
>-Lisa Marasco, LLLL, IBCLC
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 Donna J. Spannaus-Martin, Ph.D., MT (ASCP)
 Assistant Professor, Clinical Lab Sciences, Univ. of TN, Memphis
 http://www.utmem.edu/allied/CLS.html