THE PHYSIOLOGICAL ASPECT 301 
frog may be kept in a state of full bodily vigour for months, or 
it may be for years ; but it will sit unmoved. It sees nothing ; 
it hears nothing. It will starve sooner than feed itself, 
although food put into its mouth is swallowed. On irritation, 
it jumps or walks; if thrown into water it swims. If it be 
put on the hand it sits there, crouched, perfectly quiet, and 
would sit there for ever. If the hand be inclined very gently 
and slowly, so that the frog would naturally tend to slip off, 
the creature’s fore paws are shifted on to the edge of the hand, 
until he can just prevent himself from falling. If the turning 
of the hand be slowly continued, he mounts up with great care 
and deliberation, putting first one leg forward and then 
another, until he balances himself with perfect precision on the 
edge ; and if the turning of the hand is continued, he goes 
through the needful set of muscular operations, until he comes 
to be seated in security on the back of the hand. The doing 
of all this requires a delicacy of co-ordination and a precision of 
adjustment of the muscular apparatus of the body which are 
only comparable to those of a rope-dancer.” 
Now, why have we entered into these details ? To rein- 
force, from a somewhat different point of view, that which has 
again and again been urged in the preceding sections of this 
inquiry, that much of animal behaviour is an organic legacy. 
A going mechanism of great delicacy, with ready-made co- 
ordinations, the products of biological evolution, affords to 
consciousness a vast body of its primary data. As Dr, Sher- 
rington himself says,* “ co-ordination is abundantly shown to 
result from the independent power of the spinal arcs, altogether 
apart from the influence of the great cranial sense-organs, and 
of the cerebral arcs superposed upon them. These senses and 
the brain find the elementary co-ordination of the skeletal 
musculature an achievement already provided and to hand in 
the spinal cord. And no doubt the product of the instrument 
is, with the instrument itself, given over to their use in the 
reactions they elicit from the spinal musculature.” We have 
seen how instinctive behaviour, in those animals in which it is 
* Op. cit., pp. 20, 21. 
