but it is, we believe, an admitted fact that all good breeds require constant supervision and
occasional introduction of fresh blood to prevent deterioration.
Though it is allowable to assume t h a t variation is possible, and that many even of natural
species, especially local varieties, may have had a common origin, the position is greatly
weakened by attempting to trace for it a universal application; and though many of the
wonderful instincts to be found in wild animals and in the inferior forms of life are very probably
referable to t h e hereditary transmission of acquired habits, on this account to take for
granted that all are acquired and none inherent raises a host of difficulties at once; and it
is here that some of t h e arguments in support of t h e hypothesis of modified descent appear
overstrained: for instance, in his seventh chapter, on instincts, Mr. Darwin attributes the
origin of t h e well-known parasitic h a b i t s of our European Cuckoo t o t h e gradual prevalence
of an occasional and accidental action of an ancestor, t h e progeny which imitated her, through
a supposed advantage thereby obtained i n t h e struggle for existence, gradually exterminating
the progeny which did not, till the instinct became universal. Now this can hardly account
satisfactorily for t h e entire prevalence of the habit i n one species only; for the advantage
gained is at best so trifling that it would constantly be overbalanced by individual variations in
strength and intelligence quite independent of t h e h a b i t : and t h e only other inference t o be
drawn from it is too flattering to t h e Cuckoos as a body to be accepted; for it leads us to infer
t h a t in the whole race not a single individual is to be found sufficiently short-sighted and
imprudent to neglect so trifling an advantage, while among the Swallows and other
migratory birds not a single individual, from the beginning of time until now, has had the
wit t o hit on so simple an expedient; for if one had hit on it, there is as much reason to
assume that t h e cunning Swallow's progeny would have extermmated the others as there
is in t h e case of t h e Cuckoos.
I t will be found difficult, also, to reconcile this universal prudence on the part of the
Cuckoos with the theory of the common descent of all organized beings, when we consider
t h e infinite variety of form and intelligence displayed in t h e animated creation. We know
t h a t many a wise man begets a fool, and doeth it to his sorrow; and why t h e Cuckoos should
enjoy such complete immunity we cannot say. It is t r u e t h a t t h e rejection of this explanation
lands us in the dilemma of believing that an Allwise Creator endowed a portion of His
creatures w i t h an instinct apparently subversive of t h e maternal affections; but as even on the
other hand we must admit tha t this instinct has grown out of the unrestrained action of His
law, it is not a wide step further to believe t h a t it was from the beginning a peculiarity of
t h i s species, and that we have as yet failed to fathom the true intention.
Again, t o take another instance, t h e individuals of t h e species Tinnunculus alaudarius,
TJrrua coromanda, and many other ltaptorial birds, which occasionally make use of the
deserted nests of Crows and other large birds, as is well known to observers of Nature,
should have gained an equally great, if not greater, advantage in t h e struggle for existence,
in t h e increased leisure obtained to seek for food, and the habit ought long ere now to have
become universal with them. In the same way the putting on of dull green or brown
plumage, so essential to small forest-birds to protect them from the observation of their
enemies, should have been acquired by all, instead of being confined to a few only, as is the
case. The most striking case of all is perhaps that of the females of the Swallow-tailed
Butterfly, Papilio memnon, assuming the form and colouring of P. coon, another somewhat
similar Butterfly; the eminent naturalist who first drew attention to t h e fact, ascribed it to
t h e immunity that the group to which the latter belongs, enjoys from the attacks of birds,
and t h a t in this way the mimicking females escape from persecution. We have often watched
t h e Indian representatives of these species, which exhibit the same peculiarity, but have not
noticed that any of them were specially liable to the attacks of either birds or dragonflies, so
t h a t we cannot from our own experience substantiate this p o i n t ; granting, however, that it
is so, we have a fnost astounding fact—out of a single batch of eggs, in one portion the
transition to another species (supposed to require countless minute gradations and links) complete
in a single birth, in the remaining portion the change not even commenced, and no
intermediate stage. If this extraordinary phenomenon is to be attributed to an external
cause, it would be worth while considering whether this results from a fixed law of instinct
or from volition—if the latter, by whose volition it is performed, by t h a t of the parent or by
that of the offspring—also why the whole batch do not adopt the remedy, and, lastly, how
the question is settled as to which shall put on t h e deceptive livery and which remain victims.
The facts are marvellous; but t h e explanations are more puzzling still.
As regards the minute variations in colouring and size which separate closely allied species,
and especially slight differences peculiar to local distribution, we cannot consider that they
offer any obstacle to a belief in t h e common origin of t h e species so allied, though it has not
as yet been sufficiently proven for us t o insist upon i t : neither, on t h e other hand, is i t part
of our zoological faith to maintain that all gaps in form were once filled up by a countless
series of links—though to admit that they may have been so connected opens out a wide field
for inquiry, of the deepest interest, and gives a renewed zest to t h e collection of facts bearing
on the subject. Especially valuable are such researches as those of Mr. A. B. Wallace,
which reveal to us so much of the really natural history of the animal kingdom, and which
enable us to compare the results arrived at through the observations of domesticated animals,
and of those whose conditions of life have been modified by t h e encroachments of civilization,
with those of which the conditions have been uninfluenced in any way by man. Though it
is quite t r u e t h a t man does not produce variability, i t is nevertheless certain t h a t by changing
t h e conditions of life he calls into play that which was previously dormant; and the observations
of animals in civilized countries only can never carry the same amount of conviction
in support of an hypothesis as those carried on in a wild country and on animals in a primitive
state. To the assertion that there is no obvious reason why the principles that have acted so
efficiently under domestication should not have acted under nature, we reply that there is a
reason to be deduced from the very obvious fact that the wild Dog, t h e wild Fowl, the wild
Duck, the wTild Pigeon, the wild Cat, the wild Horse, remain to this day single species,
while of the domestic varieties claiming descent from them the name is legion—a fact
almost conclusive in showing that these principles do not act where the conditions of life
are invariable, but that where these have changed, cither through man's influence, climate,
or any other cause, t h e capability of variation has from time to time most probably been
b