608 The Reasoning Faculty of Animals. (August, 
rant habits of their mother, and in their turn would be apt to lay 
their eggs in other birds’ nests, and thus be more successful in _ 
rearing their young.”! This explanation seems to us simple, and 
at the some time adequate, and the same process of reasoning 
applied to all instincts of like character, would with little modifica- 
tion be sufficient. Such instincts as the last, the hive bee cells, 
the case of butterflies laying eggs on plants, the slave-making 
habits of ants, and many more which will recur to any one, are 
brought into existence accidentally, and given a tendency to 
variation in any faculty of the mind or power of the body, and we 
can expect to see it modified by nature’s seizing upon the favor- 
able variations, transmitting them in an improved state each time 
by inheritance from one generation to another, until they reach 
such perfection that men are astonished, and can see no other 
way of accounting for the fact, but by bringing to their aid 
divine power and intervention. 
Now we are told, that instinct is some power or principle 
possessed by animals, by means of which they perform, blindly 
and ignorantly, works of an intelligent nature; further, an im- 
pulse by which they are directed, without previous instruction OF 
experience, to do unerringly what is necessary for the preserva- 
tion of the individual or the species. The fact that instincts are 
not unerring, goes far to prove that they had some such origin aS 
we have described. It is known, for instance, that butterflies and 
moths often lay their eggs upon plants or in positions where their 
larve can not flourish? What is this but a return to a former 
method of proceeding, when the insect laid her eggs on any 
plant? Here the instinct fails utterly, and not only does not a5 
sist in the preservation of the species, but is instrumental in 
destroying it. Cattle are supposed to know by instinct poisonous 
from beneficial plants, but take them to a new country, and they 
at first are as likely to eat the poisonous ones as those that are 
not. Their so-called instinct fails, because it is not an instinct at 
all, but the result of experience and observation. The instinctive 
dread birds have of man is often spoken of; but that is no instinct 
either. Birds and animals of all kinds in a state of nature, where 
? Origin of Species, 6th ed., N. Y., p- 212. 
Kirby and Spence, loc. cit. 11, 466, say that the flesh fly sometimes lays her &88° 
in the flowers of Stapelia hirsuta, instead of in carrion, and further that the common 
house fly will frequently deposit her eggs in the snuff in a box. 
