86 NATURE AND LIFE. * 
the tissues, excepting one only, may thus be renewed in the 
system, when they have been destroyed in it by any pro- 
cess, and they are reproduced in accordance with the same 
rules that govern their appearance and their development 
in the embryo state. Robin, who has expressed this law, 
extends it to the production of morbid tissues also. Be- 
sides the restoration of the tissues, the naturalist notes 
also that of some organs. The famous experiments of 
Spallanzani have placed beyond question the reproduction 
of the limbs and tail of the salamander. The restoration 
of the tails of lizards has been always known, only that no 
vertebrz had been remarked in the newly-formed append- 
age. Charles Legros has lately found that vertebra do 
appear in it at the end of two years after amputation. He 
has also effected the complete reproduction of the eyes and 
of a part of the head of salamanders, from which he had cut 
off the entire head with scissors, only sparing the brain. 
He has also procured the new growth of a tail in dormice ; 
but he did not succeed in keeping the animals long enough 
to give the vertebrz time to make their appearance within 
the organ. 
These phenomena show us one and the same law gov- 
erning the various exhibitions of the power of evolution, in 
disease as in health. We find in the facts, already well 
known, of animal-grafting, other remarkable proofs of that 
power. LBert’s experiments have shown, from a new point 
of view, how certain animal organs may be removed from 
place, and transferred to a part of the system which is not 
their original home, and may yet continue living there. 
We may even transfer and graft tissues from one kind of 
animal upon another kind; we may inject the blood-glob- 
ules of one animal into the veins of an animal of another 
species, and these globules in that new place discharge 
their peculiar function. There are cases in which animals, 
and men also, brought by loss of blood into a state of seem- 
