348 
ON INSTINCT. 
be supposed to have passed through the mind of the wasp, or its 
actions are altogether inexplicable. Instinct might have taught 
it to cut off the swings of all flies previously to flying away with 
them ; but here it first attempted to fly with the wings on—was 
impeded by a certain cause—discovered what this cause was, 
and alighted to remove it. The chain of evidence seems perfect in 
the proof that nothing but reason could have been its prompter. 
To larger animals few philosophers deny some share of reason, 
but it is not generally accorded to insects; yet however difficult 
it may be to form a clear conception of this union of instinct and 
reason in the same operation, or to define exactly the limits of 
each, instances of these mixed actions are sufficiently common 
among animals to leave no doubt of the fact. It is instinct 
which leads a greyhound to pursue a hare, but it must be reason 
that directs an old greyhound to trust the more fatiguing part of 
the chase to the younger, and to place herself so as to meet the 
hare in her doubles*.^^ 
The fact seems to be, that we, the little lords of the creation, 
are too prone to measure the sentient principle in animals by the 
scale of our own ideas, and thus unwillingly allow them to 
possess faculties which may surpass our own, though peculiarly 
appropriate to their respective natures. A little reflection 
must compel us to confess, that they are endowed with discri¬ 
minating powers totally unknown to and for ever unattainable by 
man. But we will proceed higher up this imaginary chain of 
beings which we are contemplating, and take the birds for our 
observation. 
It is towards the period of the birth of the young that the 
mothers put in requisition all the resources of their instinct; 
first, in the construction of the nest, and every species having 
an instinct and industry peculiar to itself, constructs its nest 
in its own peculiar way. The care of building the nest oftener 
devolves upon the female than the male, who seldom does more 
than collect and transport the materials with which she operates. 
Some males even do not give themselves any trouble about the 
matter, but leave the whole of the burden on their wife; and 
whilst she is busily engaged in binding and interlacing the sprigs of 
dried plants, giving the first form and solidity to the habitation, 
pressing in the materials which she has accumulated, and sepa¬ 
rating and arranging them by the movements of her body, so as 
to make a comfortable home for herself and family, her good-for- 
nothing husband is warbling his soft notes to another fair song¬ 
stress of the grove. After the birth of the young ones, we find 
her busily engaged both in their education and in the amiable 
♦ Spence on Instinct. 
