EE 
THURSDAY, APRIL 3, 1873. 
ORIGIN OF CERTAIN INSTINCTS 
APHe writer of the interesting article in NATURE 
of March 20 doubts whether my belief “that many 
of the most wonderful instincts have been acquired, inde- 
pendently of habit, through the preservation of useful 
variations of pre existing instincts,” means more than 
“that in a great many instances we cannot conceive how 
the instincts originated.” This in one sense is perfectly 
true, but what I wished to bring prominently forward was 
simply that in certain cases instincts had not been ac- 
quired through the experience of their utility, with con- 
tinued practice during successive generations, I had in my 
mind the case of neuter insects, which never leave off- 
spring to inherit the teachings of experience, and which 
are themselves the offspring of parents which possess 
quite different instincts. The Hive-bee is the best known 
instance, as neither the queen nor the drones construct 
cells, secrete wax, collect honey, &c. If this had been 
the sole case, it might have been maintained that the 
queens, like the fertile females of humble-bees, had in 
former ages worked like the present neuters, and had 
thus gradually acquired these instincts; and that they 
had ever afterwards transmitted them to their sterile off- 
spring, though they themselves no longer practised such 
instincts. But there are several species of Hive-bees 
(Apis) of which the sterile workers have somewhat diffe- 
rent habits and instincts, as shown by their combs. 
There are also many species of ants, the fertile females 
of which are believed not themselves to work, but to be 
served by the neuters, which capture and drag them to 
their nests ; and the instincts of the neuters in the diffe- 
rent species of the same genus are often different. All 
who believe in the principle of evolution will admit that 
with social insects the closely allied species of the same 
genus are descended from a single parent-form ; and yet 
the sterile workers of the several species have somehow 
acquired different instincts. This case appeared to me 
so remarkable that I discussed it at some length in my 
“ Origin of Species ;” but I do not expect that anyone who 
has less faith in natural selection than I have, will admit 
the explanation there given. Although he may explain 
in some other way, or leave unexplained, the development 
of the wondrous instincts possessed by the various sterile 
workers, he will, I think, be compelled to admit that they 
cannot have been acquired by the experience of one gene- 
ration having been transmitted to a succeeding one. I 
should indeed be glad if anyone could show that there was 
some fallacy in this reasoning. It may beadded that the 
possession of highly complex instincts, though not de- 
rived through conscious experience, does not at all pre- 
clude insects bringing into play their individual Sagacity 
‘in modifying their work under new or peculiar circum- 
stances ; but such sagacity, as far as inheritance is con- 
cerned, as well as their instincts, can be modified or 
injured only by advantage being taken of variation in the 
minute brain of their parents, probably of their mothers. 
The acquirement or development of certain reflex 
actions, in which muscles that cannot be influenced by 
the will are acted on, isa somewhat analogous case to that 
No, 179—VOL. vit. 
| NATURE 
417 
of the above class of instincts, as I have shown in my re- 
cently published book on Expression ; for consciousness, 
on which the sense of utility depends, cannot have come 
into play in the case of actions effected by involuntary 
muscles. The beautifully adapted movements of the iris, 
when the retina is stimulated by too much or too little 
light, is a case in point. 
The writer of the article in referring to my words 
“the preservation of useful variations of pre-existing 
instincts” adds “ the question is, whence these variations?” 
Nothing is more to be desired in natural history than 
that some one should be able to answer such a query, 
But as far as our present subject is concerned, the 
writer probably will admit that a multitude of variations 
have arisen, for instance in colour and in the character 
of the hair, feathers, horns, &c., which are quite inde- 
pendent of habit and of use in previous generations. 
It seems far from wonderful, considering the com- 
plex conditions to which the whole organisation is ex- 
posed during the successive stages of its development 
from the germ, that every part should be liable to occa- 
sional modifications : the wonder indeed is that any two 
individuals of the same species are at all closely alike. 
If this be admitted, why should not the brain, as well as 
all other parts of the body, sometimes vary in a slight 
degree, independently of useful experience and habit ? 
Those physiologists, and there are many, who believe 
that a new mental characteristic cannot be transmitted 
to the child except through some modification of that 
material sub-stratum which proceeds from the parents, 
and from which the brain of the child is ultimately deve- 
loped, will not doubt that any cause which affects its 
development may, and often will, modify the transmitted 
mental characters. With species in a state of nature such 
modifications or variations would commonly lead to the 
partial or complete loss of an instinct, orto its perver- 
sion ; and the individual would suffer. But if under the 
then existing conditions any such mental variation was 
serviceable, it would be preserved and fixed, and would 
ultimately become common to all the members of the 
species. 
The writer of the article also takes up the case of the 
tumbling of the pigeon, which habit, if seen in a wild 
| bird, would certainly have been called instinctive ; more 
especially if, as has been asserted, it aids these 
birds in escaping from hawks. He suggests that 
it “is a fancy instinct, an outlet for the overflowing 
activity of a creature whose wants are all provided 
for without any exertion on its part;” but even on 
this supposition there must have been some physical 
cause which induced the first tumbler to spend its over- 
flowing activity in a manner untike that of any other bird 
in the world. The behaviour of the ground-tumbler or 
Lotan of India, renders it highly probable that in this 
sub-breed the tumbling is due to some affection of the 
brain, which has been transmitted from before the year 
1600 to the present day. It is necessary gently to shake 
these birds, or in the case of the Kalmi Lotan, to touch 
them on the neck with a wand, in order to make them 
begin rolling over backwards on the ground. This 
they continue to do with extraordinary rapidity, until they 
are utterly exhausted, or even, as some say, until they 
die, unless they are taken up, held in the hands, and 
AA 
43 re i ha , 
