9:59:59.000,9:59:59.000
Our story is about a girl named Iris.

9:59:59.000,9:59:59.000
Iris is very sensitive.

9:59:59.000,9:59:59.000
So much that she is always in tears.

9:59:59.000,9:59:59.000
She cries when she's sad,

9:59:59.000,9:59:59.000
when she's happy,

9:59:59.000,9:59:59.000
and even tears up when things just get to her.

9:59:59.000,9:59:59.000
She has special lacrimal glands to make new tears

9:59:59.000,9:59:59.000
and special tubes, called lacrimal puncta,

9:59:59.000,9:59:59.000
to drain old ones away.

9:59:59.000,9:59:59.000
And she cries so much that she goes through

9:59:59.000,9:59:59.000
ten ounces of tears per day,

9:59:59.000,9:59:59.000
30 gallons a year!

9:59:59.000,9:59:59.000
In fact, if you look closely,

9:59:59.000,9:59:59.000
you'll see that she's crying a little bit all the time.

9:59:59.000,9:59:59.000
The basal tears that Iris constantly produces

9:59:59.000,9:59:59.000
form a thin coating of three layers,

9:59:59.000,9:59:59.000
that cover her and keep dirt and debris away.

9:59:59.000,9:59:59.000
Right next to Iris is the mucus layer,

9:59:59.000,9:59:59.000
which keeps the whole thing fastened to her.