pancreatic juice 1-1/2
intestinal juice 1/2
-------
21-1/2

Do not fancy this is all wasted or lost. Very far from it: for the whole
process seems to be a second circulation, as it were; and, while the blood
is moving in its wonderful passage through veins and arteries, another
circulation as wonderful, an endless current going its unceasing round so
long as life lasts, is also taking place. But without food the first would
become impossible; and the quality of food, and its proper digestion, mean
good or bad blood as the case may be. We must follow our mouthful of food,
and see how this action takes place.

When the different juices have all done their work, the _chyme_, which is
food as it passes from the stomach into the duodenum or passage to the
lower stomach or bowels, becomes a milky substance called _chyle_, which
moves slowly, pushed by numberless muscles along the bowel, which squeeze
much of it into little glands at the back of the bowels. These are called
the mesenteric glands; and, as each one receives its portion of chyle, a
wonderful thing happens. About half of it is changed into small round
bodies called corpuscles, and they float with the rest of the milky fluid
through delicate pipes which take it to a sort of bag just in front of the
spine. To this bag is fastened another pipe or tube--the thoracic
duct--which follows the line of the spine; and up this tube the small
bodies travel till they come to the neck and a spot where two veins meet.
A door in one opens, and the transformation is complete. The small bodies
are raw food no more, but blood, traveling fast to where it may be
purified, and begin its endless round in the best condition. For, as you
know, venous blood is still impure and dirty blood. Before it can be
really alive it must pass through the veins to the right side of the
heart, flow through into the upper chamber, then through another door or
valve into the lower, where it is pumped out into the lungs. If these
lungs are, as they should be, full of pure air, each corpuscle is so
charged with oxygen, that the last speck of impurity is burned up, and it
goes dancing and bounding on its way. That is what health means: perfect
food made into perfect blood, and giving that sense of strength and
exhilaration that we none of us know half as much about as we should. We
get it sometimes on mountain-tops in clear aut