DR. A. R. WALLACE ON THE PROBLEM O F UTILITP.
481
THEPROBLEM
OF UTILITY: Are Specific Characters always or
R. WALLACE,
LL.D., F.R.S.,
generallyUsefu1 ? By ALFRED
F.L.S.
[Read 18th June, lS96.1
TEE above stated question is discussed a t great length in the
second port of t h e late M r . Romanes’ work o n ‘Darwin and After
Darwin,’ fully half of the volume being devoted t o i t ; and in t h e
preface the author states his belief that his arguments are so conclusive that he has “broken t o fragments” t h e doctrine of utility,
and that be has “ made a full eud thereof.” A careful perusal o f
the volume, and a full consideration of all t h e facts and arguments adduced therein, seem to m e t o leave t h e problem just
where i t was before ; but t h e variety of t h e subjects discussed,
t h e great mass of details refcrred to, and t h e ingenuity of some
of t h e arguments in support of the author’s view, lead me t o
think that I have not hitherto set forth t h e facts and arguments in favour of t h e utility-theory R i t h sufficieut completenew.,
while I am indebted to t h e lamented author f o r pointing out one
or t w o weak points in my discussion of t h e question, and for a
number of useful references to Darwin’s statements on the
points a t issue, some of which I had overlooked. Although
Mr. Romanes’ discussion of t h e question is so lengthy, the
problem itself is in its essence a comparatively simple one, and
is I believe capable of being solved by a reference t o well-known
facts and admitted principles. The reason why Mr. Bomanes is
xble to support his views by so many quotations from Darwiu’s
works, is due to t h e fact that Darwin was firmly convinced
o f t h e heredity of acquired characters, and especially of t h e
influence of food and climate and t h e effects of use and disuse ;
and this belief must be borne in miud whenever be speaks of
specific characters being due t o other causes than natural
selection. It must also be remembered t h a t Darwin was not
acquainted with the evidence we now possess as t o t h e estremc
frequency of variation everywhere in nature, its large amount,
and its universality in every organ and every character that can
be measured or otherrrisc estimated. Had h e known what we
now know an this subject, he would not so frequently have niade
t h e proviso-“ if they vary, for without variation natural selection
can do nothing,” or have alluded t o t h e possibility of variations
of the same kind occurring “ perhaps after a long interval of
LINN. J0URN.-ZOOLOGY,
VOL. XXV.
40
482
DR. ALFRED R . WALLACE ON
time.” W e now know t h a t variations of almost every conceivable
kind occur, in all tho more abundant species, in every generation, and that the material for natural selection to work upon
is nerer wanting. Accepting, then, these facts of variation, and
always keeping in mind t h e severity of t h e struggle for existence,
nine tenths at least of the progeny of the higher animals perishing
annually before reaching maturity, t h u s leading t o a systematic
mid contiuual weeding o u t of t h e less fit-let us endeavour t o
realize tlie process of t h e forniation of new species and the
nature of t h e characters which distinguish allied species from
each other.
In m y article o n “ Mimicry and other Protective Resemblances
among Animals,” first published i n 1867, I laid down the
principle of utility, perhaps a little too absolutely, i n the following
passage :- “ Perhaps n o principle has ever been announced so
iertile in results as that which Mr. Darwiu so earnestly impresses
upon us, and which is iudeed a necessary deduction from the
theory of Natural Selection, namely-that none of the definite
facts of organic nature, no special organ, 110 characteristic
form o r marking, 110 peculiarilies of instinct o r of habit, no
relatioils b e h een speties or between groups of species, can
exist b u t which must now be o r oiice have been U S e f h l t o t h e
individuals or raccs wliich posbess them.” Professor Huxley,
in hi3 obituary notice of Dcirwi:i, cxpressed t h e same idea as
follows :-“ Every variety which is wleetrd into a species is
favoured and preherved in coilsequence of being, in some one
or niore respects, better adapted t o its surroundiiigs t h a n its
rivals. . . F o r , as has been pointed out, it is a iiecessary
consequence of the theory of Selection that erery species niust
have some one or more btructural or t‘iinctional peculiarities, i n
virtue of the advantage conferred by which it has fought through
the crom d of its competitors and achiercd a c e r h i n duration. 111
this sense it is t r u e that every specica has been ‘ originated by
selection.’ ” Now these characters, in i i r t u e of uhich t h e
variety has become a species, ale iu fact its “specific characters,”
and they alone will absolutcly diKerentiate i t from all other
species. We ueed not trouble ouraelies about the cases of
doubtful species, in hich t h e distiiictive cliaractcrs are either so
niinute or so unstable that we callnot invariably determine
them. On tbe theory of evolution by natural selection tliere
must be such cases. They are qieciies iii the mahiiig and iiot
. .
483
THE PllOBLEM OF UTILITY.
quite completed. But in t h e great majority of species definite
characters do exist by which a n y single individual can be
recognized and the species t o which it belongs be determined ;
a,nd the question is, whether or no t h e characters, or combination
of characters, which thus dift’imwtiate it are now useful or were
useful a t t h e time of its originatiou*. I n order t o auswer this
question, we must briefly suinninrize both t h e facts aucl t h e
admitted principles or theories which bear upon it.
Every extensive area coiitnins a number of large aucl dominant
species which aI?pe,zr to be, aiid probably am tor coueiderablc
periods, stable, both in iivcrage population and in t h e exteut of
t h e area they occupy. Taliin:. m y one of these species-say
of bird o r mammal--so long as the whole conditions of its
environment reniain uircliniigod o r rcry little changed i t mill,
theoretically, continue t o iirttinlain itself, 21s w e Itnow m a n y
species h a r e inaintained tliciuhelres duriug the i hole period
since the glacial epoch, and some very inucli longer. The
species, ho~z-ever,is not absolutrly homogeneous. It varies i n
: ~ swas former1.v
every genei,ation, n o t niiiiutrly o r iufinitc~sin~ally
supposed, b u t very consiilcrxbly, the variations being easily see11
aiid measured by a n y oiic wlio looks for thcm ; :idthey estcutl,
SO far as w e know, t o every p i ’ t of the organism, cxtrrnd and
internal, since 110 part lixx j e t been found to he iurmiuble \vlren
a large number of iucliritludw have becn cainparcxl. The specit,s
is therefore c~niposedo f L: lluctuatiiig inass of vnrinblt? uliits
which yet maintain t h e siinit! gtitertil averaqe of chnr:xc+cbrs, u i ~ i
this it cau only (lo by a const:int or interinittent wrciliiig o u t of
the extremes in every dircctiotr. Such a qcediiig out 0 1 1 n large
scale takes place aniruallp, bcc;iusc~,sltliongh t!te aiii~uiilincream
by birth is very Inrgc, the piipu1:ition of ntiults renr:iins approximately fixed. Tlie apecic’s is ni;tiiit;tined in Iiarniuiiy wiih its
euvironment by tlic surviv;tl of tho fittvst.
B u t now l e t soiiie inipoitxiit c1i:nige occur, c.ither in calimate,
i n abundance of food, or by tlic: irruption of so:iie new aiid
hitherto unknown eneniics, m ch;iiige which at first iiijurioualy
* To this ~lioulclbe aclded-*‘ or were corrohted with sottte useful oI1;uactera.”
1 h ; ~ r oreferred to such correlations in uty ‘ iV:ltur:il
Nature,’ pp. 173 and 175; and iis to alqmmntly useless ch;~rac.tembeing i t t
some cases correlated with tlioso w l i i u h :ire uscfitl, in tiiy ‘ Lhrwitiistit,’ p. 1-10 ,
but it is cumbersome to restate t h i H p r r t of’ the theory whenwcr it is sht;.(l
that all specific cbnriLoterrj are uscful.
40 *
484
DB.. ALFRED R. WALLACE ON
affects the species. It must, therefore, undergo some amoiint of
modification, either structural or functional, in order to succeed
under the new conditions ; and the constant variations of every
part around its mean furnish the materials for adapting the
organiam to these new conditions. If a new enemy is the
danger t o be guarded against, t h i s adaptation may be effected in
several ways. Swiftnew in running or flying, habits of concealment, o r seeking new kinds of food in places inacessible t o the
enemy, may each lead to the survival of those individuals which
were sufficient!y intelligent to adopt tlietn or sufficiently favoured
by rapid variation in the desired direction. Survival of the fittest in
these respects, going on year by year, might lead t o the formation
of two or more diverging races each able to maintain itself in the
presence of the new enemy, while the former average type of
the species rapidly became extinct. W e should thus have two
or three incipient new species ; but they would not become well
differentiated species till they had acquired certain definite and
inportsnt characteristics. These are (1) some amount of infertility when crossed with the parent form or with each other; and
(2) some distinct and conspicuous external characters by means
of which the new varietieR could readily distinguish their own kind
even when a t consiaerable distances or when partially concealed ;
or, in the case of flowering plants, be distinguished by the insects
which fertilize them.
The grextest danger to a species under new and adverse
conditions is, that it should not be able t o adapt itself t o them
with sufficient rapidity. It is for this reason that, as Darwin
concludes, new species arise, mainlv, from those which have ft
large popillation, which occupy a s i d e area, and which present
much variation-a combination rarely found except in continental
areas. B u t this danger is evidently much increased if crossing
with the parent form is not a t first checked and soon afterwards
completely prevented, except as a quite exceptional occurrence.
The means of preventing this intercrossing are, for animals,
either infertility, external distinctious leading to the preferential
mating of similar forms, or physical isolation. The latter I
believe, with Darwin, t o be of comparatively little importance
and to have very rarely been the chief agent in modification. I n
the great majority of cases a new species iiiust arise amidst the
population of an existing species; and while its adaptation is
progressing any intercrossing with the parent form will be
THE PROBLEM OF UTILITY.
485
injurious. I have endeavoured to show, and can still find no flaw
in my reasoning, that mutual infertility would be usually
brought about by natural selection wherever the two f o r m were
in contact, and also that t h e early occurrence of well-marked
external differences would assist greatly in the rapidity ot'
adaptation *. This view will explaiu t h e curious fact of the wellmarked differences of colour or form which almost invariably
characterize allied species. These '' recognition marks," as I have
termed them, are of great use even to existing well-defined species,
b u t they must have been of still greater use during the earlier
stages of differentiation, when t h e very existence of the new
form must have largely depended on them.
I may here remark that i t is because these external differences
of colour or markiug are quite as constantly preseut i n peculiar
insular species as i u those inhabitiug a coutinent, tliot I do uot
believe in local isolation as of any importance in species-formation.
Insular species may have been pruduced in two ways. Either
a portion of a decliuing species may have reached the island,
where i t survived through the inore favourable couditions while
it became extinct on the continent; or, a few individuals of a
dominaut species reaclied the island, where, owing to the absence
of cornpetition, they rapidly increased till t h e islaud became fully
stocked with the unchanged species. Theu (and then only) s u r vival of the fittest wouid begin t o act, and the differeuces of'
food and climate, with the cligerent Binds of enemies, would render
some modifications of structure, form, or colour advantageous, anti
t h u s a new species would be formed by adaptation froin the old
one in almost exactly the same way as on the coutinent. 111
both these cases recognition-characters, t o aid in the prevention
of intercrossing, would be produced by natural selection. But
if insular species h a r e usually been formed by a few individuals
somewhat different froin the type having first reached ttic
island aud thereafter preserved their peculiarities, there is 110
reason why auy distiuctive and stable form of coloration or
marking should have been developed, since there would be no
similar species from which i t would neeJ t o be ditfereiitiatecl.
Neither is the sniall arnouiit of divergence t h a t usually prevails
between t h e mean of a few iudividuals taken at random, such ;LS
niight have accidentally reuched an island, and the average t y p
*
' Darwinism,' pp. 174-180.
486
DX. ALFRED B. WALLACE OX
of t h e species, a t all comparable with the well-marked charactera
that usually distinguish insular forms, aud there is nothing in
mere isolation witliout selection which can increase t h e difference.
As examples w e may refer t o t h e many peculiar species of
butterflies and birds found in the various islands of t h e West
Indiau and M a l a j an Archipelagoes, which are quite as distinct
from each other as are allied continental species, and which
exhibit all the characteristics of forme which have been fully
differentiated by natural selection.
The sketch uow given of the usual mode of forniation of new
species under natural selection lezds to t h e conclusion that every
species (of the higher animals at a11 events) will usually possess
a t least three peculiarities : in t h e firht place, it must exhibit
some diffcmtice of structure or function adapting i t t o new conditions ; secondly, some distinction of colour, form, or peculiar
ornament serving as distinctive recoguition marks ; and, thirdly,
t h e physiological peculiarity of some amount of infertility wheu
crossed with allied species. The first two constitute its " specific
characters." B u t if we conhider that every species i n t h e long
line of its ancestry must have liad similar specific characters,
adaptiug i t to t h e peculiar conditions of its environment aud
distinguishing i t from its nearest allics ; that some of these
characters, when generally uxef ul, have persisted, and now constitute generic or family characters ; that others have been agaiu
and again modified so as to adapt them t o new and sometimes
quite different condilions ; and that othcrs again, becoming useless, persist when quite harmless or remain in a more o r less
rudimentary condition ; and when we further consider that mauy
genera and families extend far back into geological time and must
have originated in the midst of a physical and biological environment very diffrrent from that which now prevails, Re shall dimly
understand how complex are the forces and processes which have
led to t h e assemblage of characters now presented by each
organism, and bow difficult i t must be t o determine positively
t h a t any one of these characters is not, nor ever has been, useful
t o its possessor. Yet this is what is done by those writers who
maintain, as did t h e late Mr. Romanes, that t h e majority of'
specific characters are not and never have been useful, but
have arisen through definite variation under the influence of'
definite causes, and, when neither useful nor hurtful, persist and
constitute t h e main external differences which we observe beta een
THE YBOBLEM OF UTILITY.
487
species and species. This theory, which, although to some extent
held by Darwin himself, I eoiisider t o be wholly erroneous, we
will now proceed t o discuss.
It may b e well first t o dispose of a point, made much of by
Mr. Eomanes, that I do not urge utility as a characteristic either
of varieties or of genera a n d higher grotips, and that i t is therefore illogical to claim i t for species. But this is a misapprehension,
since I do claim that wlieri varivties are constant, a,re hereditary,
and occupy a definite area, and are therefore what Darwin termed
“incipient species,” t h e characteristics which distingtiish them
from t h e parent species are, t o some extent, adaptive and useful,
and will become fully so when t h e variety becomes n fully differentiated species. A n d as t o genera and families, i t is obvious
that every one of their distiuguishing characters was once 3
specific character, since genera are merely groups of species, all
of which were derived from one parent species, and which have
become more or less isolated by the extinction of intermediate
forms. Families are, in t h e same way, derived from a single
genus and ultimately froin a single species, and the same reasouing
applies t o them. The reason why my argument on this question
has been limited to species is, because t h e whole problem is included in that of species: i t is i n them t h a t the process and
lams of development can be best studied free from many of those
complexities of modification and survival of disused and partially
aborted parts and organs wliicli often comtitute generic or family
characters. If‘ every one of the new characters o r new combinations of characters which arise when a new species become3
every one of these ia
d i f h e n t i a t e d from its pareut-form,-if
adaptive and utilitarian, then n o higher gronps can posesu
characters other than those which were once adaptive, siiice
genera and families call never acquire new charactem except
through every one of their component species acquiring those
characters. The problem as exhibited i n species includev therefore t h e problem i n all higher groups.
I have already set forth ill some detail the argument f o r utility
founded on the fact of t h e continuoils progress of the discovery
of utilities with t h e continuous growth of our knowledge of the
life-histories and inter-relations of plants and animals *. I will
therefore now devote more special attention t o the fundamental
argument, that whereas every modification of a species which
* ‘ Darwinism,’ pp. 131-142.
498
DR. ALFRED It. WALLACE ON
arises under the influence of natural selection must, from the
very nature of its origin, be useful to the new form, no other
agency has been shown to exist capable of producing non-utilitarian characters in every individual constituting a species, neither
more nor less. NOW
the general cause which is adduced as being
able to do this is stated by Darwin in the followiug passages, which
are quoted by Mr. Romanes as expressing his own views :" There must be some efficient cause for each slight individual
difference, a s well as for more strongly marked variations which
occasionally arifie j and if the unknown cause were t o act persistently, it is altnost certain that all the individuals of the species
would be similarly modified '' (' Origin of Species,' p. 171).
Again, after referring to cleivtogarnic flowers and degraded
parasitic animals, he says :" W e are ignorant of the exciting cause of the above specified
modifications; but if the unknown cause were to act almost
uniformly for a length of time, we may infer that the result
would be almost uniform ; and in this case all the individuals of the
species would be modified in the same manner" (' Origin,' p. 175)".
Now these passages, merely as stating a possibility or a probability, appear t o me to be wanting both as regards logic and
in the absence of any appeal to the actual facts of variation.
For the argument is, briefly, that the same causes will alwsys
produce the same or closely similar results. B u t this is only true
when the same causes act upon identical materials and under
identical conditions. B u t the very foundation of the Darminian
theory is, that the materials-the
individuals of a species-are
not identical, but that they vary indefinitely and in many directions
even under closely similar conditions. How then can any external
cr internal causes produce an identical result-a definite new
variation-in all the individuals of a species, born as they are of
varying parents, of different ages, and subject to ever fluctuating
conditions? It seems to me, therefore, that the ci priort probabilities are all against Darwin's supposition.
Now let us see how far the f u c i s of variation give any support
t o the theory of useless specific characters. I f there is one
thing better established than another i t is that the individual
variations which are constantly occurring in all common species
* I n my 'Darwinism,' p. 141, I have stated my opinion that Darwin did not
believe in the production of useless characters in all the individuals of a species.
I had overlooked the paesages quoted by Mr. Romanes and given above, which
certainly show that he did believe it.
THE PROBLLM OF UTILITY.
459
are indefinite in their character and very uiiequal in their amount.
Some species are much niore variable than others, and Darwin
has shown reasons for believing t h a t auy chauge of couditions
induces variability, but not tliat it causes definite variations.
Tlie two things are radically distinct. So far as I am aware, 110
evidence has beeu adduced of ally special conditions which have
produced a definite variation in t h e wliole offspring of all the
individuals subjected to it. B u t it must do more tiIan this. F o r
i t must produce a variation so exceptionally stable t h a t it constantly recurs in all the offspring of successive generations, even
though those off;ipriug are subjected to considerable change of
conditions, as are t h e individuJs of all species except t h e rarest
or the most local. Only with such couvtancy and stability of
inheritance could a useless character become fixed in every individual of a species, which it must be t o be a " specific" cliaracter.
It must, therefore, from the very first have been invariablc.
B u t this feature of invariability without selection has not been
found t o characterize any variation, whether occurring among
wild o r domesticated orgmisnis. Such an occurreiice would
necessarily have forced i t d f upon t h e atteiitioii ot' breeders aud
horticulturists. Fur if tlie theory iu true tliat the majority of
specific characters are of this useless kind, their occurrence :is
permanent and unchangeable variations must be a coninion phenomenon, and we ought to find that foreign plauts \\-hen first
cultivtited very often presvnt new characters, not sporadically
b u t appeariug i n every iudividual, aud which cannot he got rid
of, since they do not vary and selection would therefore be
powerless t o eliminate them. Has any indication of a phenomenon
of this kind ever been noted?
Let u s come now t o tile actual causes said t o produce useless
specific characters. Accordiug to Mi.. Ronianes tliey are five
i n number : Cliniate, Food, Sexual Selection, Isulation, and Laws
of Growth. L e t US consider liow tliese are known t o act or a r e
alleged to act. Climate and Food undoubtedly produce modification in the individual, but it has not get been proved that tlieae
modifications are hereditary. I f this could be proved tlie whole
discussion on the heredity of acquired cliiLracters would be settled
i n t h e affirmative. The supposed proof that these causes produce
definite changes which a r e hereditary is derived from tile fact
t h a t there is often a simultaneous change i n t h e colours of many
animals, or in t h e forin or texture of the foliage of' inaiiy plants,
in diEerent parts of the area they occupy wliich are cliaracterizcd
490
DR. ALFRED
11. WALLACE
On
by differences of climate. But i n every caae these changes can
be interpreted as adaptations for protection i n t h e case of the
animals, and as either adaptations or inriividual non-hereditary
modifications in the case of the plants. The firm belief that such
individual characters were usually, if not always, inherited led t o
some looseiiess in Darwin’s reasoning on this point, and still
more so in t h a t of most modern upholders of the theory.
The next alleged cause, Scxua.1 Selection, whether Ke limit i t ,
as I do, to the struggles of the males, leading t o the development
of’s-eapons and defensive armour, or with Darwin extend it to the
choice b y t h e females of the more ornamental males, thus leading
t o the development of decorative plumes &c., is really a form of
natural selection, and sexual characters are therefore useful characters. It is true that, from my point of view, male distinctive
colour and ornament have notthis particular use; and Mr.Roniane3
makes a good point against me when he says that in imputing
their origin and developmeiit t o the surplus vitality and energy
of the male I give away my case, since I admit that useless
specific characters may be developed independently of natural
sclection. This is owing t o my having omitted. t o lay special
stress o n the specz$c part of‘ each ornament being really a
“ recognition mark,’’ and therefore essential both to t h e first
production and subsequent well-being of every species. I n t h e
summary of my argument (‘ Darwinism,’ p. 295) 1 hare adduced
the need of recoglition as t h e cause of specific specialization of
colour, b u t in the body of my discussion as t o sevrial ornaments
I have n o t rcferred to it, and this omission greatly weakens my
argument. I should hare said that tlie accessory plumes and
other ornanieuts originate at points of great nervous and
muscular excitation, and are developed through surplus energy ;
aud that, from their first appearance, they were utilized for
purposes of recognition, which explains both their comparative
stability in each species 2nd their distiuctuess in allied forms *.
*
Since writing this paper I have carefully studied Professor Weisniann’s
new theory of “Grrniirial Selection,” w b i d l seems to me to have a higli degree
of probabilit,y, and which, if true, enablrs us to explain two phenoineua which
have not, hitherto been fiillg esplicable. The,% are (1) the complete or almost
romplete clisappearunce of many characters which have bccoriie useless ; and
(2) the development of secondary sexual characters far beyond the poiut of
utility :is recognition marks, and, apparrnt,ly, up to the extreme poiut of
incipient hurtfulness. I t thus furnishes the one link neceesary in the cliain of
argument proving t hat thefie secondary sesual chnracters are explicable without calling in the very problematical agency of female choice.
T E E PROBLEM O F UTTI,ITY.
491
The next alleged cause, Isolation, I do not admit t o be a u c ~ a
It is, at most, au aid to
t h e differentiation of new species by natural sclectiou.
T h e last alleged cause, t h e Laws of Growth, cau never, of
itself, account for specific characters, b u t only for those struct u r a l aiid histological peculiarities of orgtliiismv which characterize
t h e higher groups such as classes and sometimes perliaps orders
and families ; and ereu these must always, when they first
originated, have had a utilitariaii character, since i t is almost
impossible t o conceive that tlie details of structure of t h e v:trious
tissues or organs produced under t h e action of these l a ~ wcrc
s
absolutely iudiffereut t o the well-being of t h e organism.
I f , theu, \re admit, as I do adinit, that certain growtlis,
appendages, or mirltinga, which are of 110 use to the orgallism,
do occasionally appear, n o agency has been adduced which could,
first, cause thcsc uselesd characters t o appear in every individual
of a species, and then totally cease to appear whenever any
portion of this spccies is scslcctwl and slightly inotlified so as to
occupy a new place i n nature or t o save itself from extinction by
some new enemy. Wlieiievor uselcss clraract,ers arc said t o be
" specific," it seeins to be forgotten that oiie species Ii:is always
passed continuously into another b y a process of normal individual variation a:id survival of the fittest. Tliere is no clrapiti
in such a process, no sutldcn transition from one creature to
another of a different nature. The traiisition is by a purely
normal aiid nltiross iinperceptilh process of adaptation to 11ew
conditions, and iii itself f'utmisliea 110 reason whatever why a n y
useless character, it' i t hacl ronstantly reappeared iu t h e
countless milliotis of individuals during all the iiiillioiiv of
geiierations of the c1ur:itioti of the species, should n t oixe
disappcar, o r be rcplnccd by some new chnract. r equally iiitiversal, equally iiirariable, and cqiially useless.
I stsoiigly urge, therefore, that tlie gcncral causes sugqcsted
by Darwin as possibly lradiug t o the production of unclesr
specific characters, as well as the more special cause3 enurncrated
by Mr. Ro~iiaiiei,do not apply t o t h e actual ticts of varhtion
and heredity so far as t1iC.y are j e t known t,o us ; and further,
that nu attetnpt has bee11 iiinde to show, even hypothatically,
how, through t h e nctioii of kuo\i-ir cauaes, such characters, M lien
they do arise, caii become first exteuded t o every individual of a
species, and then be totally obliterated as regards any portion of
t h e species which may become modified 80 as to constitute a new
causa a t all, for rcasous already given.
492
DR. ALFRED 1L WALLACE ON
species. Uwful characters tlius strictly limited are the necessary
and logical results of modification through survival of the fittest.
No agency has been shown to exist capable of producing useless
characters similarly limited. And as it is beyond the powers of
human reasou t o know absolutely that any characters YO limited
as to be really specific are and alnays have been useless, it is
both unscientific aud illogical to pothdate such characters as
being present in all or many species, and therefore as constituting an essential characterivtic feature of specific forms.
The preceding discussion inay, I hope, be considered sufficient
t o show tliat useless specific characters, if they exist, can only
be the result of some comparatively rare and exceptional COYditions, and that they certainly are not, as has been alleged, a
general cbaracteristic of species ; but it may be as well to notice
a few of‘ the special cases which hare been adduced by Mr.
Rornanes aud others as examples of their existence or as illustrating their form a t’1011.
The Niata cattle of South America, which have strangely
upturned jaws, are siiid to breed very true and to form a definite
well-marked race a hich, if the character were not injurious but
simply indifferent, might lead to the forination of a species
defiued by this useless specific character. The short-legged
Ancon sheep, and the six-toed cats, are other examples of sucli
remarkable abnormalities or sports which have the curious
property of beiug strongly hereditary, and yet, apparently, of
never leading t o the formation of new species. Almost all
students of evolution now admit that “sports” or large and
sudden divergencies from the specific t.ype are not the materials
from which uew species have been formed, the reason beiug that
they are extremely rare occurrences; and when any such
‘‘ sport ” appeared in a species, the iiidividual presenting it would
either be avoided by its fellows and leave no offspring, or by
repeated crossings with the normal type the sport would disappear.
W e may, no doubt, imagine conditions under which a sport of
this kind, once appearing in both sexes, might lead t o the
formation of a breed and ultimately of a wpecies; b u t the
combiiiatiou of conditions requisite to bring this about is so
improbable that we can only look upon it as a bare possibility.
But the question we are disccssing is not whether, under certain
very rare aud exceptional condkions, a few species may possibly
be formed which are distinguished only by altogether useless
characters, but whether such charactem are common in the
THE PROBLEM OF UTILITY.
493
majority of species and, t o use Mr. Romanes’ words, exist iu
“enormous numbers.” The case of abnormal sports o r moilstrosities such as those here referred to can certainly not be
adduced as giving any support t o this view.
The next case, that of the Porto Santo rabbits, is held by
Mr. Komanes to prove that the constant characters which distiuguished them from coninion rabbits were ouly results of the
action of peculiar conditions on individuals, and were not produced
by natural selection. H e arri\ es at this conclusion from the fact
that one of‘ the two which died a t tlie Zoological Gardens after
four years’ captivity was sent to Darwin, who found that the
spccial colouring that distinguished the breed-the absence of
black on the tail and ear-tips and the reddish colour on the
back-had almost disappeared, and that the whole colouring was
very little different from that of the common wild rabbit. Hence
Mr. Rornaues concludes that other wild species may be really
only climatal forms, and their peculiar characters be nonadaptive. But no mention is made of the remarkably small size
of these rabbits, which were only about half the weight of the
common wild species and which looked no larger than average
rats. If this also were a result of the action on the individuals
of scanty food or a peculiar climate, it would have rapidly
disappeared with ample food a t the Zoological Gardens; and
neither in this point nor in the peculiar form of t h e posterior
end of the skull and interparietal bone, which was SO distinct
that Darwin figured it (see ‘ Animals and Plants under Domestication,’ i. p. l l S ) , did he note any difference in the dead auirnal.
It seems probable, therefore, that the colour-peculiarities of the
Porto Santo rabbits were due to a change of tint of the longer
hairs which may have been lost during the illness which led to
the animal’s death. And as we have no information as to the
supposed change having been progressive during the four years
of confinement, or that i t affected the second specimen, no such
conclusion as that drawn by Mr. Romanes can be held to be
established.
The only other case of much importance is that oE changes of
colour said t o be directly causcd by changes of climate, and
especially by darkness in cave-animals. I n this latter case i t is
declared by Mr. Romanes that the loss of colour canuot be of
any use and cannot have been caused by natural selection. It
is, therefore, an example of a useletls character occurring in all
the individuals of many unconnected species. I n the case of the
494
DR. A L F R E D R. WALLACE O N
Proteus, however, i t is stated that when subjected to the action
of light in confinement, the skin becomes dark, showing that the
character is in some degree an individual one, due probably t o
deficiency of nutrition or, partiall!., to the need of light for the
secretion of the pigment. The whiteness is here not a specific
character. And if, in other cases, i t is perniauent and specific,
it may have had a very obvious use i n the early stages of the
modification of a cave-fauna. For if any animals were isolated
in caTerns which were not totally dark, the light tiuts would be
important a8 recoguition marks, euabliug the sexes t o fiiid each
other; and when, at a later period, the species spread into the
parts which were totally dark, there would be no cause leading
to a return of the positive colour, especially a4 all caTe-animalu
subjected t o total darlriiees must a t first have been in great
danger of extinction from deficiency of food, aud there would
thus be no surplus nourishment available for the production
of pigments.
Several biological frieuds with \\horn I have discussed this
question, n hile agreeing thnt the ma.jority of specific charnctcrs
me useful, have suggested that useless charslcters map have been
produced in some such manner as the f~llowing. If some iiscless
character appears as a variation in some individuals of exceptional vigour, it may increase by interbreediug, and its repeated
production being perhaps favoured by some locnl conditions, it
may come t o form B marked local variety. Now, if the coiiditioiis
become untivourable to the species in the area occupied by the
tjpe, this may in course of time become extinct, and the variety
distinguished by the altogether useless cliaracter ill remain as
the only representative of the species. It may be admitted that
such a inode of origiu of a nou-utilitarim specific character is
conceivable, but whether i t ever actually occurs in nature may
be doubted ; while if it does occur, i t must he owing t o ho rare a
combination of circumstances that it can produce 110 such general
prevalence of useless specific characters ae is claimed by the
advocates of that theory *.
I n order to ascertain whether the immediate autecedent to
such a mode of species-formation as is suggested is at all comnon,
and thiukitig that Britibb floweriug plants offer the best m a h i a l s
for its detection, I put the case t o two experienced British
* If, ho-ever, the variation is preserved because i t occurs in excrptiunally
vigorous lndividuals, it is correlated with a character which is useful.
TUX PROBLEM OF UTILITY.
495
botanists as follows :-Are there any examples within your knomledge of well-marked varieties (not mere individual states diie t o
local conditions) Ehicli occupy a considerable area to the exclusion of t h e parent species, and which do not occupy atuy area,
or only a very small one, with the type ? Each of thern sugqested
several species which seemed t o a n s n e r t o t h e coiiditioiis, b u t
on further consideration i t appeared that they did not do so, and
we were finally reduced t o a singlc case, that of one of tlie species
of Rubus, a genus which ino,st botanists will regard as a very
uns‘ifc one t o draw any couclusions from. R Z L ~roduln,
U S Welhi~,
is said to be abundant i n ilie &Iidland p n t s of E ~ g l a i i db, u t in
the Southern a i d S o ~ t l i - ~ o s t e i ~counties
ii
to be replnced by Ilic
variety ccnglicccnus of W. M. Rogers, the type never Iiaviiig been
found i n t h e area occupied by tliis variety. If this is thc caw,
aiid the two forms, said t o 11e easily recognizable, re:dly occupy
distinct areas arid nomliere overlap, or very slightly so, then u e
have t h e condition preceedoiit to the formation of a sprcios by t h c
extinction of tlie t j pe, thus leaving t h e variety to rcpresrnt t h e
species. Of course i n this c:xse n c do uot know that the cIinr,ictc.rs
wliicli distinguish t h e unricaty are useless ; b u t if they are so,
and if the variety should p ” e s s some superior vigour of coilstitutiori or other useful peculiarity which ei~nblesi t t o survive
when the t j p e dies out, TITC slioulci liave an illuutration ofone inode
in 1% liich u s e l e s specific characters may possibly l i a ~e nriben.
The enyuir) is lutereding, howcver, bocnuse i t bririzs l o light
t h e rather unespected f x t , t k t t fi\ecl varieties of phiits occupying corisiderable areas to the excluhiou of the type are not
corninon, and, perhaps, in o u r i a l , ~ n ddo not exist. And sliould
they be found t o occur more frequ(3utly iii other coiiiitiies-:is
rarieties of bird., niarrimals, :111d reptilea do occur 111 separate
areas in North America-they
inny be usually esplinecl as
aclaptatioiis to very differelit climiitic coiiditions, in v Iiic.11 cme
the diatiiiguishiirg charncters 13 111 b e utilitarian, and tlie local
varieties will be rually iucipient apecieu.
T h e preceding enquiry leads us t o certain very dcfiiiite conclusions. 111 tlic first place, w e see tliat q e c i e s , n11ic.h have been
differentiated as such by the laws of variation and survival of
t h e fittest, must be characterized by certain peculiarities nlierehy
they have obtaiiied an advautagc i u the struggle ~vith tbcir
fellows. These pecu1i:witica coiiutitute their “ specific cliitructers,“
496
MESSRB. T. B. JONES AND F. CIIAPXISN ON TEE
and these must be useful. As this applies also to every species
in the direct line of descent, the Characters which are sectional or
generic must also, at the time of their origin, have been useful.
I n the second place, although non-utilitariau characters do
undoubtedly appear in the normal course of variation, no agency
has yet been detected adequate to the extension of these useless
peculiarities to all the individuals which constitute a species,
and, further, to prevent their extension to any of the varieties
which are destined to become new species. Unless the power in
question can have this twofold effect it cannot lead, except by
accident, to the production of useless specific characters.
Under conceivable conditions, however, it is possible that certain
useless characteristics may become limited t o the individuals of a
single species. Biit what we know of the modes of variation
and the distribution of varieties iudicates that, if at any time so
produced, they must be altogether exceptional and of the nature
of chance products j and that they cannot possibly constitute
such a general characteristic of species as has been suggested.
Our final conclusion is that, whether we can discover their
use or no, there is an overwhelming probability in favour of the
statement that every truly specific character is or has been
useful, or, if not itself useful, is strictly correlated with such a
character.
On the Fistulose Polymorphince, and on the Genus Ramulina.
By T. RUPERTJONES,
F.R.S., and F. CHAPMAN,A.L.S.,
F:R.M.S.
[Read 16th January, 1896.1
PART
I.
The Fistulose Polynaorphime.
IT having been suggested that the several specimens referred to
the genus Ramulina, Rupert Jones, may possibly belong to
fistulose Polymorphince," this memoir has been undertaken to
show what evidence there is for c)r against the suggestion.
With this object in view, it is necessary for us to define the
special PoZynaorphince which bear extraneous growths of fistulose
form. Therefore, in the first place, we propose to take a survey
of the known fistulose, tubulose, and racemose Polymorphina.
* F.B.BALEWILL
and F.W. MXLLETT.-"The Foraminifera of Galway.
Journ. Yimosc. Nat. hi., TO^. iii. 1884, p. 33.