ter 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 this all. If digestion were a thing to be trifled with, I might
sup upon lobster, and the matter of life of the crustacean would undergo
the same wonderful metamorphosis into humanity. And were I to return to
my own place by sea, and undergo shipwreck, the crustacean might, and
probably would, return the compliment, and demonstrate our common nature
by turning my protoplasm into living lobster. Or, if nothing better were
to be had, I might supply my wants with mere bread, and I should find
the protoplasm of the wheat-plant to be convertible into man, with no
more trouble than that of the sheep, and with far less, I fancy, than
that of the lobster.

Hence it appears to be a matter of no great moment what animal, or what
plant, I lay under contribution for protoplasm, and the fact speaks
volumes for the general identity of that substance in all living beings.
I share this catholicity of assimilation with other animals, all of
which, so far as we know, could thrive equally well on the protoplasm of
any of their fellows, or of any plant; but here the assimilative powers
of the animal world cease. A solution of smelling-salts in water, with
an infinitesimal proportion of some other saline matters, contains all
the el