108 REVERSION, NOT A LAW, SUI GENERIS. 



Of the second law, Darwin speaks, at much length, 

 in Chapter xxvn, of Vol. ii, of Animals and Plants, 

 &c. This law, also, is matter of common knowledge. 



Of the third law, — viz., the reproduction of lost limbs, 

 in the course of the same generation in which they 

 were lost, — evidence perhaps may better be produced, 

 as it is a matter not so generally known. 



"It is notorious" (says Darwin) "that some of the 

 lower animals, when cut into many pieces, reproduce 

 so many perfect individuals. Lyonnet cut a Nais, or 

 freshwater worm, into nearly fifty pieces, and these all 

 reproduced perfect animals. It is probable that seg- 

 mentation could be carried much further in some of 

 the protozoa, and, with some of the lowest plants, each 

 cell will reproduce the parent form" (pp. 429, 430, Vol. 

 ii, Animals and Plants, &c). 



The power of this reversion, or ability, of any 

 organism to recomplete itself, when any part or parts 

 have been cut off, is such, that a mere fragment, taken 

 from a Begonia leaf, will re-develop the whole plant, if 

 imbedded in fit soil, and kept at an appropriate tem- 

 perature. So small, frequently, is the fragment which 

 is capable of reproducing for itself the whole plant 

 from which it is torn, that something like a hundred 

 plants, may be produced from the fragments of a 

 single leaf. If this power be kept down by adverse 

 conditions, is it any wonder that, upon the return of 

 the favorable conditions, to a plant which has had a 

 part or organ missing for ten, a hundred, or a thousand 

 generations, it should regain its integrity, byre-develop- 

 ing such part or organ ? 



