302 Friends and Foes 



The bark of oaks, elms and willows, is made suffi- 

 ciently unpleasant to most animals by the presence of 

 tannin; and ferns contain so much of this that few 

 animals care to eat them, though they have their own 

 particular caterpillars. 



Many plants are not merely disagreeable, but even 

 poisonous to mammals, though birds may eat the seeds, 

 and insects the leaves, with impunity; and others again 

 are of such a biting flavour as to raise blisters on the 

 tongue or skin. Some members of the buttercup 

 family are of this acrid nature, and the buttercup itself 

 is said to be avoided by cattle ; but on the other hand, 

 the deadly nightshade, which is fatal to man, is eaten 

 with impunity by the rabbit. 



The Asclepias gigantea of the desert is so deadly 

 that the least drop of the poisonous milk contained in 

 its leaves and stem causes total blindness if it touches 

 the eye ; and even those who cut the plant for fire- 

 wood must beware of so much as touching their eyes 

 afterwards, since a merely accidental rub may deprive 

 them of sight. 



One would suppose, therefore, that the asclepias 

 was so amply protected as to have no enemy at all ; 

 yet there is one upon which its deadliness makes no 

 impression whatever; and this, the goat, devours it 

 greedily, though all other animals refuse and avoid it. 



Goats are indeed the most omnivorous and most 

 destructive of animals, and very few plants, or even 

 trees, are safe from them. Neither the thorns of the 

 prickly pear, nor the flinty ' needles ' of young pines 

 and firs afford any sufficient protection against them ; 

 and yet even the goat has its preferences, and is said 

 to refuse lettuce, while it will eat cabbage. 



