How much Work the Heart Does.~--The heart is a small organ, only about as large as your fist, and yet it does an amount of work which is almost beyond belief.

Each time it beats, it does as much work as your arm would do in lifting a large apple from the ground to your mouth.

It beats when we are asleep as well as when we are awake.

When we run we know by the way in which it beats that it is working very fast.

Do you know how much a ton is?
Well, in twenty-four hours the heart does as much work as a man would do in lifting stones enough to weigh more than one hundred and twenty tons.
~13.