THE WONDER OF LIFE 571 



The Wonder of Regeneration. — It is striking to see 

 how from -within its cuticular sheath there suddenly bursts 

 forth a beautifully formed lobster-limb, replacing one that 

 has been lost. It is hberated at a moult, and stretches 

 itself out like a Jack-in-the-Box. The occurrence seems 

 almost magical, but we must not be misled. The abrupt- 

 ness of the phenomenon is whoUy superficial, there has been 

 a long period of gradual differentiation within the husk 

 of the limb-bud. There are not many Jack-in-the-Box 

 phenomena in organic Nature. Her magic is quiet. 



Therefore one of the things to be borne in mind is that 

 in regenerative growth, just as in embryonic development, 

 one phase naturally and gradually leads on to the next. The 

 stump of a snail's horn will re-grow the whole horn, with 

 the eye at the tip included, and wiU re-grow it not once but 

 many times. But there is nothing sudden, the horn is 

 fashioned with a gradually increasing perfection, reminding 

 one of the growth of, let us say, a coronet in the craftsman's 

 hands. The words gradual differentiation and integration 

 do not solve any mystery, but they may save us from a 

 false impression. 



We are probably unable in the present state of science 

 to utiUze to proper advantage the analogies between cry- 

 stalhzation and growth ; but it is interesting to remember 

 that a minute fragment of alum fashioned artificially 

 into a sphere, or a cyUnder, or a lens, will, when dropped 

 into a solution of alum, develop into a perfect octahedron, 

 through what Kauber has called an imperfect embryonic 

 stage. A sphere of saltpetre will similarly regenerate a 

 rhombic prism, and any mutilation of a crystal will be 

 followed by a restoration of the normal form. Now the 

 gap between the httle spherule of alum and the perfect 



