FACTS 173 



under two categories quite opposite to each other from the 

 point of view of the consequences of experiments in 

 merotomy. 



Under the first category fall beings which, having been 

 truncated and yet surviving, regenerate their normal specific 

 form. Such, for example, are the fresh- water hydra, star- 

 fish, crab, earth-worm, axolotl, lizard. 



Under the second category fall those beings which, on 

 the contrary, having been truncated and surviving remain 

 truncated. Such are the sea-urchin, devil-fish, frog, carp, 

 serpent, and mammals. 4 



Does, then, the protoplasmic state with certain beings give 

 direction to their form as a whole, whereas with others 

 it has no influence on the form ? This would seem all the 

 more extraordinary as the animals divided up between the 

 two groups belong to the same zoological classes or branches. 

 The sea-urchin which remains truncated is an echinoderm 

 like the star-fish which regenerates its arms ; the serpent is a 

 reptile like the lizard, the frog an amphibian like the axolotl 

 and triton. 



On the other hand, if we make our experiments in mero- 

 tomy, not on adult animals, but on the larva or very young 

 embryo, we find in no matter what species that the regenera- 

 tion of the truncated parts takes place up to a certain age, 

 which is sometimes very advanced. The embryo of man 

 himself, if the chances and changes in the matrix at the 

 period when it is composed of two cells cut it in twain, gives 

 a birth of twins, each perfect and complete. 



Consequently, that which varies in the different species 

 is not the absence or presence of the faculty of regeneration 

 after being truncated, but only the age up to which the faculty 

 persists. The morpho-biological theorem is general for 

 living beings ; but, in the course of individual development, 



