246 PHILOSOPHY OF ZOOLOGY. 
web to entangle the fly: The ant-lion digs a pit-fall: The 
heron remains motionless at the margin of the pool, until 
the unwary fishes come within the reach of his long neck 
and bill: The cat kind take their prey by surprise ; while 
the wolf trusts entirely to swiftness and strength. The 
manner of beginning the feast, even after the supply has 
been secured, is very different according to the species. 
In a domesticated state, animals seem to lose the useful 
properties of this appetite, which are so essential to their 
existence in a wild state. Thus, cows which have been 
kept within doors during the winter, and supported chiefly 
on dry food, when turned out to pasture in the spring, de- 
vour, indiscriminately, every green herb, and frequently 
suffer for their indiscretion. Linxnzus tells, that when he 
visited Tornea, the inhabitants complained of a distemper 
which killed multitudes of their cattle, especially during 
spring, when first turned out into a meadow in the neigh- 
bourhood. He soon traced the disorder to the water hem- 
lock which grew plentifully in the place, and which the 
cattle, in the spring, did not know how to avoid*. We 
have been informed, that in Orkney many goslins die 
when first turned out into the hills, to pasture, in conse- 
quence of eating the leaves of fox-glove. In a wild state, 
however, this appetite directs animals with great certainty to 
the suitable objects of nourishment, and does not permit 
them to taste of those things which would injure or de- 
stroy. 
By the force of habit, this instinct may be so modified, 
as that what was disagreeable at first, shall even become an 
object of desire. By this capability of changing taste, vari- 
ous animals can accommodate themselves to new situations, 
* Lachesis Lapponica, ii. p. 136. 
