de Chagrin_, the hero becomes
possessed of a magical wild ass' skin, which yields him the means of
gratifying all his wishes. But its surface represents the duration of
the proprietor's life; and for every satisfied desire the skin shrinks
in proportion to the intensity of fruition, until at length life and the
last handbreath of the _peau de chagrin_, disappear with the
gratification of a last wish.

Balzac's studies had led him over a wide range of thought and
speculation, and his shadowing forth of physiological truth in this
strange story may have been intentional. At any rate, the matter of life
is a veritable _peau de chagrin_, and for every vital act it is somewhat
the smaller. All work implies waste, and the work of life results,
directly or indirectly, in the waste of protoplasm.

Every word uttered by a speaker costs him some physical loss; and, in
the strictest sense, he burns that others may have light--so much
eloquence, so much of his body resolved into carbonic acid, water, and
urea. It is clear that this process of expenditure cannot go on forever.
But, happily, the protoplasmic _peau de chagrin_ differs from Balzac's
in its capacity of being repaired, and brought back to its full size,
after every exertion.

For example, this present lecture, whatever its intellectual worth to
you, has a certain physical value to me, which is, conceivably,
expressible by the number of grains of protoplasm and other bodily
substance wasted in maintaining my vital processes during its delivery.
My _peau de chagrin_ will be distinctly smaller at the end of the
discourse than it was at the beginning. By and by, I shall probably have
recourse to the substance commonly called mutton, for the purpose of
stretching it back to its original size. Now this mutton was once the
living protoplasm, more or less modified, of another animal--a sheep. As
I shall eat it, it is the same matter altered, not only by death, but by
exposure to sundry artificial operations in the process of cooking.

But these changes, whatever be their extent, have not rendered it
incompetent to resume its old functions as matter of life. A singular
inward laboratory, which I possess, will dissolve a certain portion of
the modified protoplasm; the solution so formed will pass into my
veins; and the subtle influences to which it will then be subjected will
convert the dead protoplasm into living protoplasm, and transubstantiate
sheep into man.

Nor is th