438 
group of animals must be an instinct, since it could not 
be acquired through individual experience. But how if 
the conditions of acquisition are also common to the 
whole group? Thus an infant certainly learns to scratch 
itself; since, however it may itch, some considerable ex- 
perience is necessary before it learns to localise the sen- 
sation. As, however, the conditions of this acquisition 
are common to all children, all learn to scratch them- 
selves. Now in many animals this is an inherited acqui- 
sition ; they scratch themselves from the first. Whether 
the infant also inherits a structure which would develop 
into one as apt as that of the animal, cannot be ascer- 
tained ; all we know is that the infant’s nervous structure 
is too immature at first to permit the localisation of sen- 
sation. How much of the subsequent aptitude is the 
result of congenital tendency, and how much of acqui- 
sition through incidental experiences acting on a predis- 
posed organism, cannot be estimated.* 
That we require some character to distinguish the in- 
stinctive from the impulsive actions, may be readily shown. 
No one calls Breathing, Secretion, Excretion, &c., in- 
stincts. Yet these are the actions of congenital tendencies 
in the organism. ‘A hungry chick,” says Mr. Spalding, 
“that never tasted food, is able on seeing a fly. or spider 
for the first time, to bring into action muscles that never 
were so exercised before, and to perform a series of deli- 
cately adjusted movements that end in the capture of the 
insect.” Every one would pronounce this a typical 
case of Instinct. Now compare with it the following, 
which no one would class among the instincts: A new- 
born animal that has never breathed before.is able on first 
feeling the stimulus of the atmosphere to bring into action a 
very complicated group of muscles which never were so 
exercised before, and to perform a series of delicately 
adjusted movements which end in the aération and circu- 
culation of the blood. 
This contrast may lead us to the character sought. 
Understanding that every line of demarcation in psychical 
phenomena must be more or less arbitrary, and only 
justified by its convenience, we may draw such a line | 
between Impulse and Instinct. Impulses are the actions 
which from the first were fatal, inevitable, being simply 
the direct reflex of the stimulated organs. Given the 
respiratory organs and the atmosphere, Respiration is the 
inevitable result, Given the secretory organ and the 
plasma, Secretion is the inevitable result. 
choice, the action either takes place or it does not. 
Instincts ave also fatal, inevitable, but they weve not 
always so ; the element of choice intervenes; and although 
the intelligent discrimination may be a/mos¢ entirely 
lapsed, it never is wholly lapsed. The guiding sensation 
is still discriminative, selective. Hence instincts vary with 
varying conditions. Thus the wuétritive impulse which 
when unsatisfied causes the uneasiness of desire, and 
which moves the animal in search of food, is markedly 
distinguishable from the zzs¢inct which selects the appro- 
priate food and rejects all the rest. If an animal eats only 
certain kinds of food, out of many which would be nu- 
tritious, it is because these kinds have been selected by it, 
or by its ancestors. Every chicken, Mr. Spalding assures 
* The examples of dogs and horses finding their way home, however 
marvellous, cannot be affiliated on Instinct, since it is very far from common 
to the species: for one dog who finds his way home, hundreds are help- 
ess when lost. : 
NATURE 
There is no | 
5 4ee ee! Sk OR eo ee 
[ AZril to, 1873 
us, has to learn not to eat its own excrement, “They 
made this mistake invariably, but they did not repeat it 
oftener than once or twice.” He also has this remark :— 
“ Chickens, as soon as they are able to walk, will follow 
any moving object ; and when guided by sight alone they 
seem to have no more disposition togollow a hen than to 
follow a duck or a human being. Unreflecting onlookers 
when they saw chickens a day old running after me, and 
older ones following me miles and answering my whistle, 
imagined that I must have some occult power over the 
creatures, whereas I simply allowed them to follow me 
from the first. There is the instinct to follow ; and, as we 
have seen, their ear, prior to experience, attaches them to 
the right object.” 
I should rather say, “ there is the zzpulse to follow: 
and the instinct to follow the mother, or a duck, or the 
master who feeds them, is the selected action which 
becomes rapidly an organised habit.” It is cne of the 
conclusions of my work that all our involuntary and 
automatic actions, were originally voluntary, and that all 
instinctive actions were originally intelligent. In the 
case now under consideration, the impulse to follow is a 
fixed tendency ; the instinct to follow is facultative at first, 
and becomes fixed by habit, but is always, even when most 
firmly fixed, guided by discriminating feeling. 
To conclude : where there is no alternative open to an 
action it is impulsive ; where there is, or originally was, an 
alternative, the action is instinctive; where there are 
alternatives which may still determine the action, and the 
choice is free, we call the action intelligent. 
GEORGE HENRY LEWES 
HANDBOOK FOR THE PHYSIOLOGICAL 
. LABORATORY 
Handbook for the Physiological Laboratory. By E. Klein, 
M.D,; J. B. Sanderson, F.R.S.; M. Foster, F.R.S. ; 
and T, L. Brunton, M.D., D.Sc. (Churchill.) 
TUDENTS of chemistry have, for a long time, by 
means of the works of Fresenius and others, had 
the opportunity, almost unaided, of verifying for them- 
selves most of the experimental results of which they 
hear in lectures, and read in text-books ; and thus many 
are able, before they have finished their educational 
course, to obtain a thorough practical knowledge of the 
science. Such has not been the case with regard to 
physiology ; the subject is less advanced, and has pro- 
gressed more slowly ; perhaps this is because the descrip- 
tions of the methods by which the ends have been 
arrived at, as given by lecturers and writers, are incom- 
plete and insufficient, The work before us is the first 
important attempt that has been made to put the com- 
mencing physiologist in a fair position to begin original 
work on the subject, by giving him the necessary direc- 
tions for himself performing many of the fundamental 
experiments on which the science is based. Whether 
physiology in its most comprehensive sense, as under- 
stood by the authors of this work in their title, is a single 
branch of science which can be thus treated in its unity, 
or whether it ought to be divided up and incorporated 
with others already established, is a point which has not 
yet been satisfactorily settled, and which the perusal of 
this book may assist in proving. 
