REFLEX ACTION 33 
of the impulse from one part of the circlet of tentacles to 
other parts, seems to follow a direct rather than a reflex 
zourse, and there do not appear to be any specialized centres 
by which the impulses are received and then redistributed. 
In all animals in which well-differentiated nervous systems 
are found, in which there are distinct nerve-fibres and nerve- 
centres, reflex actions, simple or more complicated, occur. 
They form the initial steps leading up to the highest types 
of organic behaviour. So long as the nervous arcs—afferent 
fibres, nerve-centre, and efferent fibres—remain intact reflex 
acts may be carried out with great precision and delicacy, 
even when the higher centres, which we believe to be those of 
conscious guidance and control, have been destroyed. When, 
for example, the whole of the brain of a frog has been extir- 
pated and the animal is hung up by the lower jaw, if the left 
side be touched with a drop of acid the left lee is drawn up 
and begins to scratch at the irritated spot, and when this leg 
is held, the other hind leg is, with seemingly greater difficulty, 
brought to bear on the same spot. ‘ This,” says Sir Michael 
Foster, “at first sight looks like an intelligent choice... . 
But a frog deprived of its brain so that the spinal cord only 
is left, makes no spontaneous movements at all. Such an 
entire absence of spontaneity is wholly inconsistent with the 
possession of intelligence. ... We are therefore led to con- 
clude that the phenomena must be explained in some other 
way than by being referred to the working of an intelli- 
gence.” * But if we concede that intelligence is absent, may 
there not at least be some consciousness? Sir Michael 
Foster’s reply to such a question goes as far as we have any 
justification for going, even when we give free rein to conjec- 
ture. “We may distinguish,” he says, “ between an active 
continuous consciousness, such as we usually understand by 
the term, and a passing or momentary condition, which we 
may speak of as consciousness, but which is wholly discon- 
tinuous from an antecedent or from a subsequent similar 
momentary condition; and indeed we may suppose that the 
* «A Text-book of Physiology,” 5th edit., part iii., p. 909. 
D 
