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 

 vertebrse had been remarked in the newly -formed append- 

 age. Charles Legros has lately found that vertebras 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 vertebrae 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. Bert'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 me,n also, brought by loss of blood into a state of seem- 



