It is not simply the outward form of an animal which I can change.
The physiology, the chemical rhythm of the creature, may also be made
to undergo an enduring modification,--of which vaccination and other
methods of inoculation with living or dead matter are examples
that will, no doubt, be familiar to you. A similar operation is
the transfusion of blood,--with which subject, indeed, I began.
These are all familiar cases. Less so, and probably far more extensive,
were the operations of those mediaeval practitioners who made
dwarfs and beggar-cripples, show-monsters,--some vestiges of whose
art still remain in the preliminary manipulation of the young
mountebank or contortionist. Victor Hugo gives an account of them
in 'L'Homme qui Rit.'--But perhaps my meaning grows plain now.
You begin to see that it is a possible thing to transplant tissue
from one part of an animal to another, or from one animal to another;
to alter its chemical reactions and methods of growth; to modify
the articulations of its limbs; and, indeed, to change it in its most
intimate structure.

"And yet this extraordinary branch of knowledge has never been sought
as an end, and systematically, by modern investigators until I took it up!
Some such things have been hit upon in the last resort of surgery;
most of the kindred evidence that will recur to your mind has been
demonstrated as it were by accident,--by tyrants, by criminals,
by the breeders of horses and dogs, by all kinds of untrained
clumsy-handed men working for their own immediate ends.
I was the first man to take up this question armed with antiseptic surgery,
and with a really scientific knowledge of the laws of growth.
Yet one would imagine it must have been practised in secret before.
Such creatures as the Siamese Twins--And in the vaults of
the Inquisition. No doubt their chief aim was artistic torture,