Who Said This?

[Gene C]

I was reading to Fido, and he insisted that I post this. Who said/wrote this, and for bonus points, what book is it from?

Every one felt the peril of the hour,
but none felt the burden of it like our beloved
President. Nothing kept him from sinking
wholly underneath the load of calumny and
weighty cares that beset him day and night,
but the strong will of the man combined with
his wonderful facility in extracting comfort out
of the pleasant trivialities of every-day life.
Even his little dog Jip was instrumental in
relieving his master of some portion of the
burden, for the little fellow was never absent
from the Presidential lunch. He was always
in Mr. Lincoln's lap to claim his portion first,
and was caressed and petted by him through
the whole meal.