66 A DESERT PRUIT. 



branch and stick it in the ground under suitable condi" 

 tions, it grows into a rose tree. If you take cuttings of 

 scarlet geraniums or common verbenas, and pot them in 

 moist soil, they bud out apace into new plants like their 

 parents. Certain special types can even be propagated 

 from fragments of the leaf ; for example, there is a par- 

 ticularly vivacious begonia off which you may snap a 

 corner of one blade, and hang it up by a string from a 

 peg or the ceiling, when, hi, presto ! little begonia plants 

 begin to bud out incontinently on every side from its 

 edges. A certain German professor went even further 

 than that; he chopped up a liverwort very fine into 

 vegetable mincemeat, which he then spread thin over a 

 saucerful of moist sand, and lo ! in a few days the 

 whole surface of the mess was covered with a perfect 

 forest of sprouting little liverworts. Eoughly speaking, 

 one may say that every fragment of every organism has 

 in it the power to rebuild in its entirety another organism 

 like the one of which it once formed a component 

 element. 



Similarly with animals. Cut off a lizard's tail, and 

 straightway a new tail grows in its place with surprising 

 promptitude. Cut off a lobster's claw, and in a very few 

 weeks that lobster is walking about airily on his native 

 rocks, with two claws as usual. True, in these cases the 

 tail and the claw don't bud out in turn into a new lizard 

 or a new lobster. But that is a penalty the higher 

 organisms have to pay for their extreme complexity. 

 They have lost that plasticity, that freedom of growth, 

 which characterizes the simpler and more primitive forms 

 of life ; in their case the power of producing fresh 



