288 THE THORNY BUSH. 



them have, in fact, all the characteristics of a nail. 

 Those of the Acacia Tomentosa, for example, have 

 earned the soubriquet of " The Jungle Nail." Indeed 

 almost all trees of the mimosa and acacia tribe, which 

 form a considerable part of the bush forests, are 

 noted for their terrible thorns ; and wherever their grace- 

 ful plumes are seen, it becomes a species of warning 

 to travellers to beware how they come into contact with 

 them. Before quitting this " thorny " subject however, 

 we may add that it has generally been supposed that 

 Nature has almost universally armed the vegetation 

 of this region with these formidable weapons as a 

 protection against injury by animals, many of whom 

 are tree-feeders, who live not so much upon herbage, 

 as upon the leaves, shoots, and smaller branches of 

 the arborescent vegetation. 



In the first place bush feeding animals, like the camel, 

 will eat up the thorns with the twigs, as if they did not 

 exist. It has farther been pointed out by Dr. Hans Meyer, 

 a well-known German traveller and botanist, "that 

 these thorns are not to be regarded as a defence against 

 animals, so much as a protection against the drought 

 of a dry season which here often prevails in extra- 

 ordinary intensity." Dr. Meyer explains that this is 

 effected "by partial suppression of leaves, which be- 

 come indurated and form thorns, and these later on 

 develop into branches, and give rise to other thorns; 

 which shoot out from the stem alternately with the 

 true leaves, and form a spinal, the extremity of each 

 twig developing likewise into a sharp thorn. It is 

 self-evident," he goes on to say, "that with such a 

 suppression of foliage, there must be a corresponding 

 diminution of transpiration, and the tree is thus enabled 



