A DESERT FRUIT. 115 



ered with a perfect forest of sprouting little liverworts. Roughly 

 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 straight- 

 way 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 organisms entire from a 

 single fragment, once diffused equally over the whole body, is 

 now confined to certain specialized cells which, in their developed 

 form, we know as seeds or eggs. Yet, even among animals, at a 

 low stage of development, this original power of reproducing the 

 whole from a single part remains inherent in the organism ; for 

 you may chop up a fresh-water hydra into a hundred little bits, 

 and every bit will be capable of growing afresh into a complete 

 hydra. 



Now, desert plants would naturally retain this primitive tend- 

 ency in a very high degree ; for they are specially organized to 

 resist drought being the survivors of generations of drought- 

 proof ancestors and, like the camel, they have often to struggle 

 on through long periods of time without a drop of water. Ex- 

 actly the same thing happens at home to many of our pretty little 

 European stone-crops. I have a rockery near my house over- 

 grown with the little white sedum of our gardens. The birds 

 often pick off a tiny leaf or branch ; it drops on the dry soil, and 

 remains there for days without giving a sign of life. But its 

 thick epidermis effectually saves it from withering ; and as soon 

 as rain falls, wee white rootlets sprout out from the under side of 

 the fragment as it lies, and it grows before long into a fresh small 

 sedum plant. Thus, what seem like destructive agencies them- 

 selves, are turned in the end by mere tenacity of life into a sec- 

 ondary means of propagation. 



That is why the prickly pear is so common in all countries 

 where the climate suits it, and where it has once managed to gain 

 a foothold, The more you cut it down, the thicker it springs ; 

 each murdered bit becomes the parent in due time of a numerous 

 offspring. Man, however, with his usual ingenuity, has managed 

 to best the plant, on this its own ground, and turn it into a useful 

 fodder for his beasts of burden. The prickly pear is planted 

 abundantly on bare rocks in Algeria, where nothing else would 



