Critiques and Addresses
by
Thomas Henry Huxley
Part 4 out of 6
V. _The Celtic and the Teutonic dialects are members of the same
great Aryan family of languages; but there is evidence to show that a
non-Aryan language was at one time spoken over a large extent of the
area occupied by Melanochroi in Europe_.
The non-Aryan language here referred to is the Euskarian, now spoken
only by the Basques, but which seems in earlier times to have been
the language of the Aquitanians and Spaniards, and may possibly have
extended much further to the East. Whether it has any connection with
the Ligurian and Oscan dialects are questions upon which, of course,
I do not presume to offer any opinion. But it is important to remark
that it is a language the area of which has gradually diminished
without any corresponding extirpation of the people who primitively
spoke it; so that the people of Spain and of Aquitaine at the present
day must be largely "Euskarian" by descent in just the same sense as
the Cornish men are "Celtic" by descent.
Such seem to me to be the main facts respecting the ethnology of the
British islands and of Western Europe, which may be said to be fairly
established. The hypothesis by which I think (with De Belloguet and
Thurnam) the facts may best be explained is this: In very remote times
Western Europe and the British islands were inhabited by the dark
stock, or the Melanochroi, alone, and these Melanochroi spoke dialects
allied to the Euskarian. The Xanthochroi, spreading over the great
Eurasiatic plains westward, and speaking Aryan dialects, gradually
invaded the territories of the Melanochroi. The Xanthochroi, who
thus came into contact with the Western Melanochroi, spoke a Celtic
language; and that Celtic language, whether Cymric or Gaelic, spread
over the Melanochroi far beyond the limits of intermixture of blood,
supplanting Euskarian, just as English and French, have supplanted
Celtic. Even as early as Caesar's time, I suppose that the Euskarian
was everywhere, except in Spain and in Aquitaine, replaced by Celtic,
and thus the Celtic speakers were no longer of one ethnological stock,
but of two. Both in Western Europe and in England a third wave of
language--in the one case Latin, in the other Teutonic--has spread
over the same area. In Western Europe, it has left a fragment of the
primary Euskarian in one corner of the country, and a fragment of the
secondary Celtic in another. In the British islands, only outlying
pools of the secondary linguistic wave remain in Wales, the Highlands,
Ireland, and the Isle of Man. If this hypothesis is a sound one, it
follows that the name of Celtic is not properly applicable to the
Melanochroic or dark stock of Europe. They are merely, so to speak,
secondary Celts. The primary and aboriginal Celtic-speaking people are
Xanthochroi--the typical Gauls of the ancient writers, and the close
allies by blood, customs, and language, of the Germans.
IX.
PALAEONTOLOGY AND THE DOCTRINE OF EVOLUTION.
(THE ANNIVERSARY ADDRESS TO THE GEOLOGICAL SOCIETY, FOR 1870.)
It is now eight years since, in the absence of the late Mr. Leonard
Homer, who then presided over us, it fell to my lot, as one of the
Secretaries of this Society, to draw up the customary Annual Address.
I availed myself of the opportunity to endeavour to "take stock"
of that portion of the science of biology which is commonly called
"palaeontology," as it then existed; and, discussing one after another
the doctrines held by palaeontologists, I put before you the results
of my attempts to sift the well-established from the hypothetical or
the doubtful. Permit me briefly to recall to your minds what those
results were:--
1. The living population of all parts of the earth's surface which
have yet been examined has undergone a succession of changes which,
upon the whole, have been of a slow and gradual character.
2. When the fossil remains which are the evidences of these successive
changes, as they have occurred in any two more or less distant parts
of the surface of the earth, are compared, they exhibit a certain
broad and general parallelism. In other words, certain forms of life
in one locality occur in the same general order of succession as, or
are _homotaxial_ with, similar forms in the other locality.
3. Homotaxis is not to be held identical with synchronism without
independent evidence. It is possible that similar, or even identical,
faunae and florae in two different localities may be of extremely
different ages, if the term "age" is used in its proper chronological
sense. I stated that "geographical provinces, or zones, may have been
as distinctly marked in the Palaeozoic epoch as at present; and those
seemingly sudden appearances of new genera and species, which we
ascribe to new creation, may be simple results of migration."
4. The opinion that the oldest known fossils are the earliest forms of
life has no solid foundation.
5. If we confine ourselves to positively ascertained facts, the total
amount of change in the forms of animal and vegetable life, since the
existence of such forms is recorded, is small. When compared with the
lapse of time since the first appearance of these forms, the amount
of change is wonderfully small. Moreover, in each great group of the
animal and vegetable kingdoms, there are certain forms which I termed
PERSISTENT TYPES, which have remained, with but very little apparent
change, from their first appearance to the present time.
6. In answer to the question "What, then, does an impartial survey of
the positively ascertained truths of palaeontology testify in relation
to the common doctrines of progressive modification, which suppose
that modification to have taken place by a necessary progress from
more to less embryonic forms, from more to less generalized types,
within, the limits of the period represented by the fossiliferous
rocks?" I reply, "It negatives these doctrines; for it either shows us
no evidence of such modification, or demonstrates such modification as
has occurred to have been very slight; and, as to the nature of
that modification, it yields no evidence whatsoever that the earlier
members of any long-continued group were more generalized in structure
than the later ones."
I think that I cannot employ my last opportunity of addressing you,
officially, more properly--I may say more dutifully--than in
revising these old judgments with such help as further knowledge and
reflection, and an extreme desire to get at the truth, may afford me.
1. With respect to the first proposition, I may remark that
whatever may be the case among the physical geologists, catastrophic
palaeontologists are practically extinct. It is now no part of
recognized geological doctrine that the species of one formation all
died out and were replaced by a brand-new set in the next formation.
On the contrary, it is generally, if not universally, agreed that
the succession of life has been, the result of a slow and gradual
replacement of species by species; and that all appearances of
abruptness of change are due to breaks in the series of deposits, or
other changes in physical conditions. The continuity of living forms
has been unbroken from the earliest times to the present day.
2, 3. The use of the word "homotaxis" instead of "synchronism" has
not, so far as I know, found much favour in the eyes of geologists.
I hope, therefore, that it is a love for scientific caution, and not
mere personal affection for a bantling of my own, which leads me still
to think that the change of phrase is of importance, and that the
sooner it is made, the sooner shall we get rid of a number of pitfalls
which beset the reasoner upon the facts and theories of geology.
One of the latest pieces of foreign intelligence which has reached
us is the information that the Austrian geologists have, at last,
succumbed to the weighty evidence which M. Barrande has accumulated,
and have admitted the doctrine of colonies. But the admission of the
doctrine of colonies implies the further admission that even identity
of organic remains is no proof of the synchronism of the deposits
which contain them.
4. The discussions touching the _Eozoon_, which commenced in 1864,
have abundantly justified the fourth proposition. In 1862, the oldest
record of life was in the Cambrian rocks; but if the _Eozoon_ be,
as Principal Dawson and Dr. Carpenter have shown so much reason for
believing, the remains of a living being, the discovery of its true
nature carried life back to a period which, as Sir William Logan has
observed, is as remote from that during which the Cambrian rocks were
deposited, as the Cambrian epoch itself is from the tertiaries. In
other words, the ascertained duration of life upon the globe was
nearly doubled at a stroke.
5. The significance of persistent types, and of the small amount of
change which has taken place even in those forms which can be shown to
have been modified, becomes greater and greater in my eyes, the longer
I occupy myself with the biology of the past.
Consider how long a time has elapsed since the Miocene epoch. Yet, at
that time, there is reason to believe that every important group in
every order of the _Mammalia_ was represented. Even the comparatively
scanty Eocene fauna yields examples of the orders _Cheiroptera,
Insectivora, Rodentia_, and _Perissodactyla_; of _Artiodactyla_
under both the Ruminant and the Porcine modifications; of _Carnivora,
Cetacea_, and _Marsupialia_.
Or, if we go back to the older half of the Mesozoic epoch, how truly
surprising it is to find every order of the _Reptilia_, except
the _Ophidia_, represented; while some groups, such as the
_Ornithoscelida_ and the _Pterosauria_, more specialized than any
which now exist, abounded.
There is one division of the _Amphibia_ which offers especially
important evidence upon this point, inasmuch as it bridges over the
gap between the Mesozoic and the Palaeozoic formations (often supposed
to be of such prodigious magnitude), extending, as it does, from the
bottom of the Carboniferous series to the top of the Trias, if not
into the Lias. I refer to the Labyrinthodonts. As the address of 1862
was passing through the press, I was able to mention, in a note, the
discovery of a large Labyrinthodont, with well-ossified vertebrae, in
the Edinburgh coal-field. Since that time eight or ten distinct genera
of Labyrinthodonts have been discovered in the Carboniferous rocks
of England, Scotland, and Ireland, not to mention the American forms
described by Principal Dawson and Professor Cope. So that, at the
present time, the Labyrinthodont Fauna of the Carboniferous rocks is
more extensive and diversified than that of the Trias, while its chief
types, so far as osteology enables us to judge, are quite as highly
organized. Thus it is certain that a comparatively highly organized
vertebrate type, such as that of the Labyrinthodonts, is capable
of persisting, with no considerable change, through the period
represented by the vast deposits which constitute the Carboniferous,
the Permian, and the Triassic formations.
The very remarkable results which have been brought to light by the
sounding and dredging operations, which have been carried on with
such remarkable success by the expeditions sent out by our own, the
American, and the Swedish Governments, under the supervision of
able naturalists, have a bearing in the same direction. These
investigations have demonstrated the existence, at great depths in the
ocean, of living animals in some cases identical with, in others very
similar to, those which are found fossilized in the white chalk. The
_Globigerinae_, Cyatholiths, Coccospheres, Discoliths in the one are
absolutely identical with those in the other; there are identical, or
closely analogous, species of Sponges, Echinoderms, and Brachiopods.
Off the coast of Portugal, there now lives a species of _Beryx_,
which, doubtless, leaves its bones and scales here and there in the
Atlantic ooze, as its predecessor left its spoils in the mud of the
sea of the Cretaceous epoch.
Many years ago[1] I ventured to speak of the Atlantic mud as "modern
chalk," and I know of no fact inconsistent with the view which
Professor Wyville Thomson has advocated, that the modern chalk is not
only the lineal descendant of the ancient chalk, but that it remains,
so to speak, in the possession of the ancestral estate; and that from
the Cretaceous period (if not much earlier) to the present day, the
deep sea has covered a large part of what is now the area of the
Atlantic. But if _Globigerinae_, and _Terebratula caput-serpentis_
and _Beryx_, not to mention other forms of animals and of plants, thus
bridge over the interval between the present and the Mesozoic periods,
is it possible that the majority of other living things underwent a
"sea-change into something new and strange" all at once?
[Footnote 1: See an article in the _Saturday Review_, for 1858, on
"Chalk, Ancient and Modern."]
6. Thus far I have endeavoured to expand and to enforce by fresh
arguments, but not to modify in any important respect, the ideas
submitted to you on a former occasion. But when I come to the
propositions touching progressive modification, it appears to me, with
the help of the new light which has broken from various quarters, that
there is much ground for softening the somewhat Brutus-like severity
with which, in 1862, I dealt with a doctrine, for the truth of which I
should have been glad enough to be able to find a good foundation.
So far, indeed, as the _Invertebrata_, and the lower _Vertebrata_ are
concerned, the facts and the conclusions which are to be drawn from
them appear to me to remain what they were. For anything that, as yet,
appears to the contrary, the earliest known Marsupials may have been
as highly organized as their living congeners; the Permian lizards
show no signs of inferiority to those of the present day; the
Labyrinthodonts cannot be placed below the living Salamander and
Triton; the Devonian Ganoids are closely related to _Polypterus_ and
to _Lepidosiren_.
But when we turn to the higher _Vertebrata_, the results of recent
investigations, however we may sift and criticise them, seem to me to
leave a clear balance in favour of the doctrine of the evolution
of living forms one from another. Nevertheless, in discussing this
question, it is very necessary to discriminate carefully between the
different kinds of evidence from fossil remains which are brought
forward in favour of evolution.
Every fossil which takes an intermediate place between forms of
life already known, may be said, so far as it is intermediate, to be
evidence in favour of evolution, inasmuch as it shows a possible road
by which evolution may have taken place. But the mere discovery of
such a form does not, in itself, prove that evolution took place by
and through it, nor does it constitute more than presumptive evidence
in favour of evolution in general. Suppose A, B, C to be three
forms, while B is intermediate in structure between A and C. Then the
doctrine of evolution offers four possible alternatives. A may have
become C by way of B; or C may have become A by way of B; or A and
C may be independent modifications of B; or A, B, and C may be
independent modifications of some unknown D. Take the case of the
Pigs, the _Anoplotheridae_, and the Ruminants. The _Anoplotheridae_
are intermediate between the first and the last; but this does not
tell us whether the Ruminants have come from the Pigs, or the Pigs
from Ruminants, or both from _Anoplotheridae_, or whether Pigs,
Ruminants, and _Anoplotheridae_ alike may not have diverged from some
common stock.
But if it can be shown that A, B, and C exhibit successive stages in
the degree of modification, or specialization, of the same type; and
if, further, it can be proved that they occur in successively
newer deposits. A being in the oldest and C in the newest, then the
intermediate character of B has quite another importance, and I should
accept it, without hesitation, as a link in the genealogy of C. I
should consider the burden of proof to be thrown upon anyone who
denied C to have been derived from A by way of B, or in some closely
analogous fashion; for it is always probable that one may not hit upon
the exact line of filiation, and, in dealing with fossils, may mistake
uncles and nephews for fathers and sons.
I think it necessary to distinguish between the former and the latter
classes of intermediate forms, as _intercalary types_ and _linear
types_. When I apply the former term, I merely mean to say that as
a matter of fact, the form B, so named, is intermediate between the
others, in the sense in which the _Anoplotherium_ is intermediate
between the Pigs and the Ruminants--without either affirming, or
denying, any direct genetic relation between the three forms involved.
When I apply the latter term, on the other hand, I mean to express the
opinion that the forms A, B, and C constitute a line of descent, and
that B is thus part of the lineage of C.
From the time when Cuvier's wonderful researches upon the extinct
Mammals of the Paris gypsum first made intercalary types known, and
caused them to be recognized as such, the number of such forms has
steadily increased among the higher _Mammalia_. Not only do we now
know numerous intercalary forms of _Ungulata_, but M. Gaudry's great
monograph upon the fossils of Pikermi (which strikes me as one of the
most perfect pieces of palaeontological work I have seen for a long
time) shows us, among the _Primates, Mesopithecus_ as an intercalary
form between the _Semnopitheci_ and the _Macaci_; and among the
_Carnivora, Hyaenictis_ and _Ictitherium_ as intercalary, or, perhaps,
linear types between the _Viverridae_ and the _Hyaenidae_.
Hardly any order of the higher _Mammalia_ stands so apparently
separate and isolated from the rest as that of the _Cetacea_; though
a careful consideration of the structure of the pinnipede _Carnivora_,
or Seals, shows, in them, many an approximation towards the still more
completely marine mammals. The extinct _Zeuglodon_, however, presents
us with an intercalary form between the type of the Seals and that of
the Whales. The skull of this great Eocene sea-monster, in fact, shows
by the narrow and prolonged interorbital region; the extensive union
of the parietal bones in a sagittal suture; the well-developed nasal
bones; the distinct and large incisors implanted in premaxillary
bones, which take a full share in bounding the fore part of the gape;
the two-fanged molar teeth with triangular and serrated crowns,
not exceeding five on each side in each jaw; and the existence of a
deciduous dentition--its close relation with the Seals. While, on
the other hand, the produced rostral form of the snout, the
long symphysis, and the low coronary process of the mandible are
approximations to the cetacean form of those parts.
The scapula resembles that of the cetacean _Hyperoodon_, but the
supra-spinous fossa is larger and more seal-like; as is the humerus,
which differs from that of the _Cetacea_ in presenting true articular
surfaces for the free jointing of the bones of the fore-arm. In the
apparently complete absence of hinder limbs, and in the characters of
the vertebral column, the _Zeuglodon_ lies on the cetacean side of the
boundary line; so that, upon the whole, the Zeuglodonts, transitional
as they are, are conveniently retained in the cetacean order. And the
publication, in 1864, of M. Van Beneden's memoir on the Miocene and
Pliocene _Squalodon_, furnished much better means than anatomists
previously possessed of fitting in another link of the chain which
connects the existing _Cetacea_ with _Zeuglodon_. The teeth are much
more numerous, although the molars exhibit the zeuglodont double fang;
the nasal bones are very short, and the upper surface of the rostrum
presents the groove, filled up during life by the prolongation of the
ethmoidal cartilage, which is so characteristic of the majority of the
_Cetacea_.
It appears to me that, just as among the existing _Carnivora_,
the walruses and the eared seals are intercalary forms between the
fissipede Carnivora and the ordinary seals, so the Zeuglodonts are
intercalary between the _Carnivora_, as a whole, and the _Cetacea_.
Whether the Zeuglodonts are also linear types in their relation to
these two groups cannot be ascertained, until we have more definite
knowledge than we possess at present, respecting the relations in time
of the _Carnivora_ and _Cetacea_.
Thus far we have been concerned with the intercalary types which
occupy the intervals between Families or Orders of the same class; but
the investigations which have been carried on by Professor Gegenbaur,
Professor Cope, and myself into the structure and relations of the
extinct reptilian forms of the _Ornithoscelida_ (or _Dinosauria_ and
_Compsognatha_) have brought to light the existence of intercalary
forms between what have hitherto been always regarded as very distinct
classes of the vertebrate sub-kingdom, namely _Reptilia_ and _Aves_.
Whatever inferences may, or may not, be drawn from the fact, it is now
an established truth that, in many of these _Ornithoscelida_, the hind
limbs and the pelvis are much more similar to those of Birds than
they are to those of Reptiles, and that these Bird-reptiles, or
Reptile-birds, were more or less completely bipedal.
When I addressed you in 1862, I should have been bold indeed had I
suggested that palaeontology would before long show us the possibility
of a direct transition from the type of the lizard to that of the
ostrich. At the present moment we have, in the _Ornithoscelida_, the
intercalary type, which proves that transition to be something more
than a possibility; but it is very doubtful whether any of the genera
of _Ornithoscelida_ with which we are at present acquainted are the
actual linear types by which the transition from the lizard to the
bird was effected. These, very probably, are still hidden from us in
the older formations.
Let us now endeavour to find some cases of true linear types, or forms
which are intermediate between others because they stand in a direct
genetic relation to them. It is no easy matter to find clear and
unmistakable evidence of filiation among fossil animals; for, in order
that such evidence should be quite satisfactory, it is necessary that
we should be acquainted with all the most important features of the
organization of the animals which are supposed to be thus related, and
not merely with the fragments upon which the genera and species of the
palaeontologist are so often based. M. Gaudry has arranged the species
of _Hyaenidae, Proboscidea, Rhinocerotidae_, and _Equidae_ in their
order of filiation from their earliest appearance in the Miocene epoch
to the present time, and Professor Ruetimeyer has drawn up similar
schemes for the Oxen and other _Ungulata_--with what, I am disposed
to think, is a fair and probable approximation to the order of nature.
But, as no one is better aware than these two learned, acute, and
philosophical biologists, all such arrangements must be regarded as
provisional, except in those cases in which, by a fortunate accident,
large series of remains are obtainable from a thick and wide-spread
series of deposits. It is easy to accumulate probabilities--hard
to make out some particular case in such a way that it will stand
rigorous criticism.
After much search, however, I think that such a case is to be made out
in favour of the pedigree of the Horses.
The genus _Equus_ is represented as far back as the latter part of the
Miocene epoch; but in deposits belonging to the middle of that
epoch its place is taken by two other genera, _Hipparion_ and
_Anchitherium_[1]; and, in the lowest Miocene and upper Eocene, only
the last genus occurs. A species of _Anchitherium_ was referred by
Cuvier to the _Palaeotheria_ under the name of _P. aurelianense_. The
grinding-teeth are in fact very similar in shape and in pattern, and
in the absence of any thick layer of cement, to those of some species
of _Palaeotherium_, especially Cuvier's _Palaeotherium minus_, which
has been formed into a separate genus, _Plagiolophus_, by Pomel. But
in the fact that there are only six full-sized grinders in the lower
jaw, the first premolar being very small; that the anterior grinders
are as large as, or rather larger than, the posterior ones; that the
second premolar has an anterior prolongation; and that the posterior
molar of the lower jaw has, as Cuvier pointed out, a posterior lobe of
much smaller size and different form, the dentition of _Anchitherium_
departs from the type of the _Palaeotherium_, and approaches that of
the Horse.
[Footnote 1: Hermann von Meyer gave the name of _Anchitherium_ to _A.
Ezguerrae_; and in his paper on the subject he takes great pains
to distinguish the latter as the type of a new genus, from Cuvier's
_Palaeotherium d'Orleans._ But it is precisely the _Palaeotherium
d'Orleans_ which is the type of Christol's genus _Hipparitherium_; and
thus, though _Hipparitherium_ is of later date than _Anchitherium_,
it seemed to me to have a sort of equitable right to recognition
when this address was written. On the whole, however, it seems most
convenient to adopt _Anchitherium_.]
Again, the skeleton of _Anchitherium_ is extremely equine. M. Christol
goes so far as to say that the description of the bones of the
horse, or the ass, current in veterinary works, would fit those of
_Anchitherium._ And, in a general way, this may be true enough; but
there are some most important differences, which, indeed, are justly
indicated by the same careful observer. Thus the ulna is complete
throughout, and its shaft is not a mere rudiment, fused into one bone
with the radius. There are three toes, one large in the middle and one
small on each side. The femur is quite like that of a horse, and has
the characteristic fossa above the external condyle. In the British
Museum there is a most instructive specimen of the leg-bones, showing
that the fibula was represented by the external malleolus and by a
flat tongue of bone, which extends up from it on the outer side of the
tibia, and is closely ankylosed with the latter bone.[1] The hind toes
are three, like those of the fore leg; and the middle metatarsal bone
is much less compressed from side to side than that of the horse.
[Footnote 1: I am indebted to M. Gervais for a specimen which
indicates that the fibula was complete, at any rate, in some cases;
and for a very interesting ramus of a mandible, which shows that, as
in the _Palaeotheria_, the hindermost milk-molar of the lower jaw
was devoid of the posterior lobe which exists in the hindermost true
molar.]
In the _Hipparion_ the teeth nearly resemble those of the Horses,
though the crowns of the grinders are not so long; like those of the
Horses, they are abundantly coated with cement. The shaft of the
ulna is reduced to a mere style ankylosed throughout nearly its whole
length with the radius, and appearing to be little more than a ridge
on the surface of the latter bone until it is carefully examined. The
front toes are still three, but the outer ones are more slender than
in _Anchitherium_, and their hoofs smaller in proportion to that of
the middle toe: they are, in fact, reduced to mere dew-claws, and do
not touch the ground. In the leg, the distal end of the fibula is so
completely united with the tibia that it appears to be a mere process
of the latter bone, as in the Horses.
In _Equus_, finally, the crowns of the grinding-teeth become longer,
and their patterns are slightly modified; the middle of the shaft of
the ulna usually vanishes, and its proximal and distal ends ankylose
with the radius. The phalanges of the two outer toes in each foot
disappear, their metacarpal and metatarsal bones being left as the
"splints."
The _Hipparion_ has large depressions on the face in front of the
orbits, like those for the "larmiers" of many ruminants; but traces
of these are to be seen in some of the fossil horses from the Sewalik
Hills; and, as Leidy's recent researches show, they are preserved in
_Anchitherium_.
When we consider these facts, and the further circumstance that
the Hipparions, the remains of which have been collected in immense
numbers, were subject, as M. Gaudry and others have pointed out, to
a great range of variation, it appears to me impossible to resist the
conclusion that the types of the _Anchitherium_, of the _Hipparion_,
and of the ancient Horses constitute the lineage of the modern Horses,
the _Hipparion_ being the intermediate stage between the other two,
and answering; to B in my former illustration.
The process by which the _Anchitherium_ has been converted into
_Equus_ is one of specialization, or of more and more complete
deviation from what might be called the average form of an ungulate
mammal. In the Horses, the reduction of some parts of the limbs,
together with the special modification of those which are left, is
carried to a greater extent than in any other hoofed mammals. The
reduction is less and the specialization is less in the _Hipparion_,
and still less in the _Anchitherium_; but yet, as compared with
other mammals, the reduction and specialization of parts in the
_Anchitherium_ remain great.
Is it not probable then, that, just as in the Miocene epoch, we find
an ancestral equine form less modified than _Equus_, so, if we go
back to the Eocene epoch, we shall find some quadruped related to the
_Anchitherium_, as _Hipparion_ is related to _Equus_, and consequently
departing less from the average form?
I think that this desideratum is very nearly, if not quite, supplied
by _Plagiolophus_, remains of which occur abundantly in some parts
of the Upper and Middle Eocene formations. The patterns of
the grinding-teeth of _Plagiolophus_ are similar to those of
_Anchitherium_, and their crowns are as thinly covered with cement;
but the grinders diminish in size forwards, and the last lower molar
has a large hind lobe, convex outwards and concave inwards, as in
_Palceotherium_. The ulna is complete and much larger than in any
of the _Equidae_, while it is more slender than in most of the true
_Palaeotheria_; it is fixedly united, but not ankylosed, with the
radius. There are three toes in the fore limb, the outer ones being
slender, but less attenuated than in the _Equidae_. The femur is more
like that of the _Palaeotheria_ than that of the horse, and has only
a small depression above its outer condyle in the place of the great
fossa which is so obvious in the _Equidae_. The fibula is distinct,
but very slender, and its distal end is ankylosed with the tibia.
There are three toes on the hind foot having similar proportions to
those on the fore foot. The principal metacarpal and metatarsal bones
are flatter than they are in any of the _Equidae_; and the metacarpal
bones are longer than the metatarsals, as in the _Palaeotheria_.
In its general form, _Plagiolophus_ resembles a very small and slender
horse[1], and is totally unlike the reluctant, pig-like creature
depicted in Cuvier's restoration of his _Palaeotherium minus_ in the
"Os semens Fossils."
[Footnote 1: Such, at least, is the conclusion suggested by the
proportions of the skeleton figured by Cuvier and De Blainville; but
perhaps something between a Horse and an Agouti would be nearest the
mark.]
It would be hazardous to say that _Plagiolophus_ is the exact radical
form of the Equine quadrupeds; but I do not think there can be any
reasonable doubt that the latter animals have resulted from the
modification of some quadruped similar to _Plagiolophus_.
We have thus arrived at the Middle Eocene formation, and yet
have traced back the Horses only to a three-toed stock; but these
three-toed forms, no less than the Equine quadrupeds themselves,
present rudiments of the two other toes which appertain to what I
have termed the "average" quadruped. If the expectation raised by
the splints of the Horses that, in some ancestor of the Horses, these
splints would be found to be complete digits, has been verified,
we are furnished with very strong reasons for looking for a no
less complete verification of the expectation that the three-toed.
_Plagiolophus_-like "avus" of the horse must have had a five-toed
"atavus" at some earlier period.
No such five-toed "atavus," however, has yet made its appearance among
the few middle and older Eocene _Mammalia_ which are known.
Another series of closely affiliated forms, though the evidence they
afford is perhaps less complete than that of the Equine series,
is presented to us by the _Dichobune_ of the Eocene epoch, the
_Cainotherium_ of the Miocene, and the _Tragulidae_, or so-called
"Musk-deer," of the present day.
The _Tragulidae_ have no incisors in the upper jaw, and only six
grinding-teeth on each side of each jaw; while the canine is moved up
to the outer incisor, and there is a diastema, in the lower jaw. There
are four complete toes on the hind foot, but the middle metatarsals
usually become, sooner or later, ankylosed into a cannon bone. The
navicular and the cuboid unite, and the distal end of the fibula is
ankylosed with the tibia.
In _Cainotherium_ and _Dichobune_ the upper incisors are fully
developed. There are seven grinders; the teeth form a continuous
series without a diastema. The metatarsals, the navicular and cuboid,
and the distal end of the fibula, remain free. In the _Cainotherium_,
also, the second metacarpal is developed, but is much shorter than the
third, while the fifth is absent or rudimentary. In this respect it
resembles _Anoplotherium secundarium_. This circumstance, and the
peculiar pattern of the upper molars in _Cainotherium_, lead me
to hesitate in considering it as the actual ancestor of the modern
_Tragulidae_. If _Dichobune_ has a four-toed fore foot (though I am
inclined to suspect that it resembles _Cainotherium_), it will be a
better representative of the oldest forms of the Traguline series; but
_Dichobune_ occurs in the Middle-Eocene, and is, in fact, the oldest
known artiodactyle mammal. Where, then, must we look for its five-toed
ancestor?
If we follow down other lines of recent and tertiary _Ungulata_, the
same question presents itself. The Pigs are traceable back through
the Miocene epoch to the Upper Eocene, where they appear in the
two well-marked forms of _Hyopotamus_ and _Chaeropotamus_; but
_Hyopotamus_ appears to have had only two toes.
Again, all the great groups of the Ruminants, the _Bovidae,
Antilopidae, Camelopardalidae_, and _Cervidae_, are represented in
the Miocene epoch, and so are the Camels. The Upper Eocene
_Anoplotherium_, which is intercalary between the Pigs and the
_Tragulidae_, has only two or, at most, three toes. Among the scanty
mammals of the Lower Eocene formation we have the perissodactyle
_Ungulata_ represented by _Coryphodon, Hyra-cotherium_, and
_Pliolophus_. Suppose for a moment, for the sake of following out
the argument, that _Pliolophus_ represents the primary stock of the
Perissodactyles, and _Dichobune_ that of the Artiodactyles (though
I am far from saying that such is the case), then we find, in the
earliest fauna of the Eocene epoch to which our investigations carry
us, the two divisions of the _Ungulata_ completely differentiated, and
no trace of any common stock of both, or of five-toed predecessors to
either. With the case of the Horses before us, justifying a belief in
the production of new animal forms by modification of old ones, I see
no escape from the necessity of seeking for these ancestors of the
_Ungulata_ beyond the limits of the Tertiary formations.
I could as soon admit special creation, at once, as suppose that the
Perissodactyles and Artiodactyles had no five-toed ancestors. And when
we consider how large a portion of the Tertiary period elapsed before
_Anchitherium_ was converted into _Equus_, it is difficult to escape
the conclusion that a large proportion of time anterior to the
Tertiary period must have been expended in converting the common stock
of the _Ungulata_ into Perissodactyles and Artiodactyles.
The same moral is inculcated by the study of every other order of
Tertiary monodelphous _Mammalia_. Each of these orders is represented
in the Miocene epoch: the Eocene formation, as I have already said,
contains _Cheiroptera, Insectivora, Rodentia, Ungulata, Carnivora,_
and _Cetacea_. But the _Cheiroptera_ are extreme modifications of the
_Insectivora_, just as the _Cetacea_ are extreme modifications of
the Carnivorous type; and therefore it is to my mind incredible
that monodelphous _Insectivora_ and _Carnivora_ should not have been
abundantly developed, along with _Ungulata_, in the Mesozoic epoch.
But if this be the case, how much further back must we go to find the
common stock of the monodelphous _Mammalia_? As to the _Didelphia_,
if we may trust the evidence which seems to be afforded by their
very scanty remains, a Hypsiprymnoid form existed at the epoch of the
Trias, contemporaneously with a Carnivorous form. At the epoch of the
Trias, therefore, the _Marsupialia_ must have, already existed long
enough to have become differentiated into carnivorous and herbivorous
forms. But the _Monotremata_ are lower forms than the _Didelphia,_
which last are intercalary between the _Ornithodelphia_ and the
_Monodelphia_. To what point of the Palaeozoic epoch, then, must we,
upon any rational estimate, relegate the origin of the _Monotremata_?
The investigation of the occurrence of the classes and of the orders
of the _Sauropsida_ in time points in exactly the same direction.
If, as there is great reason to believe, true Birds existed in the
Triassic epoch, the ornithoscelidous forms by which Reptiles passed
into Birds must have preceded them. In fact there is, even at present,
considerable ground for suspecting the existence of _Dinosauria_ in
the Permian formations; but, in that case, lizards must be of still
earlier date. And if the very small differences which are observable
between the _Crocodilia_ of the older Mesozoic formations and those of
the present day furnish any sort of approximation towards an estimate
of the average rate of change among the _Sauropsida_, it is almost
appalling to reflect how far back in Palaeozoic times we must go,
before we can hope to arrive at that common stock from which the
_Crocodilia, Lacertilia, Ornithoscelida_, and _Plesiosauria_, which
had attained so great a development in the Triassic epoch, must have
been derived.
The _Amphibia_ and _Pisces_ tell the same story. There is not a
single class of vertebrated animals which, when it first appears,
is represented by analogues of the lowest known members of the same
class. Therefore, if there is any truth in the doctrine of evolution,
every class must be vastly older than the first record of its
appearance upon the surface of the globe. But if considerations of
this kind compel us to place the origin of vertebrated animals at
a period sufficiently distant from the Upper Silurian, in which the
first Elasmobranchs and Ganoids occur, to allow of the evolution of
such fishes as these from a Vertebrate as simple as the _Amphioxus_,
I can only repeat that it is appalling to speculate upon the extent to
which that origin must have preceded the epoch of the first recorded
appearance of vertebrate life.
Such is the further commentary which I have to offer upon the
statement of the chief results of palaeontology which I formerly
ventured to lay before you.
But the growth of knowledge in the interval makes me conscious of
an omission of considerable moment in that statement, inasmuch as it
contains no reference to the bearings of palaeontology upon the theory
of the distribution of life; nor takes note of the remarkable manner
in which the facts of distribution, in present and past times, accord
with the doctrine of evolution, especially in regard to land animals.
That connection between palaeontology and geology and the present
distribution of terrestrial animals, which so strikingly impressed
Mr. Darwin, thirty years ago, as to lead him to speak of a "law of
succession of types," and of the wonderful relationship on the same
continent between the dead and the living, has recently received much
elucidation from the researches of Gaudry, of Ruetimeyer, of Leidy,
and of Alphonse Milne-Edwards, taken in connection with the
earlier labours of our lamented colleague Falconer; and it has been
instructively discussed in the thoughtful and ingenious work of Mr.
Andrew Murray "On the Geographical Distribution of Mammals."[1]
[Footnote 1: The paper "On the Form and Distribution of the
Land-tracts during the Secondary and Tertiary Periods respectively;
and on the Effect upon Animal Life which great Changes in Geographical
Configuration have probably produced," by Mr. Searles V. Wood, jun.,
which was published in the _Philosophical Magazine_, in 1862, was
unknown to me when this Address was written. It is well worthy of the
most careful study.]
I propose to lay before you, as briefly as I can, the ideas to which a
long consideration of the subject has given rise in my own mind.
If the doctrine of evolution is sound, one of its immediate
consequences clearly is, that the present distribution of life
upon the globe is the product of two factors, the one being the
distribution which obtained in the immediately preceding epoch, and
the other the character and the extent of the changes which have taken
place in physical geography between the one epoch and the other; or,
to put the matter in another way, the Fauna and Flora of any given
area, in any given epoch, can consist only of such forms of life as
are directly descended from those which constituted the Fauna and
Flora of the same area in the immediately preceding epoch, unless the
physical geography (under which I include climatal conditions) of
the area has been so altered as to give rise to immigration of living
forms from some other area.
The evolutionist, therefore, is bound to grapple with the following
problem whenever it is clearly put before him:--Here are the Faunae of
the same area during successive epochs. Show good cause for believing
either that these Faunae have been derived from one another by gradual
modification, or that the Faunae have reached the area in question
by migration from some area in which they have undergone their
development.
I propose to attempt to deal with this problem, so far as it is
exemplified by the distribution of the terrestrial _Vertebrata_, and I
shall endeavour to show you that it is capable of solution in a sense
entirely favourable to the doctrine of evolution.
I have elsewhere[1] stated at length the reasons which lead me to
recognize four primary distributional provinces for the terrestrial
_Vertebrata_ in the present world, namely,--first, the _Novozelanian_,
or New-Zealand province; secondly, the _Australian_ province,
including Australia, Tasmania, and the Negrito Islands; thirdly,
_Austro-Columbia_, or South America _plus_ North America as far as
Mexico; and fourthly, the rest of the world, or _Arctogaea_, in which
province America north of Mexico constitutes one sub-province, Africa
south of the Sahara a second, Hindostan a third, and the remainder of
the Old World, a fourth.
[Footnote 1: "On the Classification and Distribution of the
Alectoromorphae;" Proceedings of the Zoological Society, 1868.]
Now the truth which Mr. Darwin perceived and promulgated as "the law
of the succession of types" is, that, in all these provinces, the
animals found in Pliocene or later deposits are closely affined to
those which now inhabit the same provinces; and that, conversely, the
forms characteristic of other provinces are absent. North and South
America, perhaps, present one or two exceptions to the last rule, but
they are readily susceptible of explanation. Thus, in Australia, the
later Tertiary mammals are marsupials (possibly with exception of the
Dog and a Rodent or two, as at present). In Austro-Columbia the later
Tertiary fauna exhibits numerous and varied forms of Platyrrhine
Apes, Rodents, Cats, Dogs, Stags, _Edentata_, and Opossums; but, as
at present, no Catarrhine Apes, no Lemurs, no _Insectivora_, Oxen,
Antelopes, Rhinoceroses, nor _Didelphia_ other than Opossums. And in
the wide-spread Arctogaeal province, the Pliocene and later mammals
belong to the same groups as those which now exist in the province.
The law of succession of types, therefore, holds good for the present
epoch as compared with its predecessor. Does it equally well apply to
the Pliocene fauna when we compare it with that of the Miocene epoch?
By great good fortune, an extensive mammalian fauna of the latter
epoch has now become known, in four very distant portions of the
Arctogaeal province which do not differ greatly in latitude. Thus
Falconer and Cautley have made known the fauna of the sub-Himalayas
and the Perim Islands; Gaudry that of Attica; many observers that of
Central Europe and France; and Leidy that of Nebraska, on the eastern
flank of the Rocky Mountains. The results are very striking. The total
Miocene fauna comprises many genera, and species of Catarrhine Apes,
of Bats, of _Insectivora_; of Arctogaeal types of _Rodentia_; of
_Proboscidea_; of equine, rhinocerotic, and tapirine quadrupeds; of
cameline, bovine, antilopine, cervine, and traguline Ruminants; of
Pigs and Hippopotamuses; of _Viverridae_ and _Hyaenidae_ among other
_Carnivora_; with _Edentata_ allied to the Arctogaeal _Orycteropus_
and _Manis_, and not to the Austro-Columbian Edentates. The only type
present in the Miocene, but absent in the existing, fauna of Eastern
Arctogaea, is that of the _Didelphidae_, which, however, remains in
North America.
But it is very remarkable that while the Miocene fauna of the
Arctogaeal province, as a whole, is of the same character as the
existing fauna of the same province, as a whole, the component
elements of the fauna were differently associated. In the Miocene
epoch, North America possessed Elephants, Horses, Rhinoceroses, and
a great number and variety of Ruminants and Pigs, which are absent
in the present indigenous fauna; Europe had its Apes, Elephants,
Rhinoceroses, Tapirs, Musk-deer, Giraffes, Hyaenas, great Cats,
Edentates, and Opossum-like Marsupials, which have equally vanished
from its present fauna; and in Northern India, the African types of
Hippopotamuses, Giraffes, and Elephants were mixed up with what
are now the Asiatic types of the latter, and with Camels, and
Semnopithecine and Pithecine Apes of no less distinctly Asiatic forms.
In fact the Miocene mammalian fauna of Europe and the Himalayan
regions contains, associated together, the types which are at present
separately located in the South-African and Indian sub-provinces of
Arctogaea. Now there is every reason to believe, on other grounds,
that both Hindostan, south of the Ganges, and Africa, south of the
Sahara, were separated by a wide sea from Europe and North Asia during
the Middle and Upper Eocene epochs. Hence it becomes highly probable
that the well-known similarities, and no less remarkable differences,
between the present Faunae of India and South Africa have arisen
in some such fashion as the following. Some time during the Miocene
epoch, possibly when the Himalayan chain was elevated, the bottom of
the nummulitic sea was upheaved and converted into dry land, in the
direction of a line extending from Abyssinia to the mouth of the
Ganges. By this means, the Dekhan on the one hand, and South Africa
on the other, became connected with the Miocene dry land and with one
another. The Miocene mammals spread gradually over this intermediate
dry land; and if the condition of its eastern and western ends offered
as wide contrasts as the valleys of the Ganges and Arabia do now, many
forms which made their way into Africa must have been different from
those which reached the Dekhan, while others might pass into both
these sub-provinces.
That there was a continuity of dry land between Europe and North
America during the Miocene epoch, appears to me to be a necessary
consequence of the fact that many genera of terrestrial mammals, such
as _Castor_, _Hystrix_, _Elephas_, _Mastodon_, _Equus_, _Hipparion_,
_Anchitherium_, _Rhinoceros_, _Cervus_, _Amphicyon_, _Hyaenarctos_,
and _Machairodus_, are common to the Miocene formations of the two
areas, and have as yet been found (except perhaps _Anchitherium_) in
no deposit of earlier age. Whether this connection took place by the
east, or by the west, or by both sides of the Old World, there is at
present no certain evidence, and the question is immaterial to the
present argument; but, as there are good grounds for the belief that
the Australian province and the Indian and South-African sub-provinces
were separated by sea from the rest of Arctogaea before the Miocene
epoch, so it has been rendered no less probable, by the investigations
of Mr. Carrick Moore and Professor Duncan, that Austro-Columbia was
separated by sea from North America during a large part of the Miocene
epoch.
It is unfortunate that we have no knowledge of the Miocene mammalian
fauna of the Australian and Austro-Columbian provinces; but, seeing
that not a trace of a Platyrrhine Ape, of a Procyonine Carnivore, of a
characteristically South-American Rodent, of a Sloth, an Armadillo,
or an Ant-eater has yet been found in Miocene deposits of Arctogaea, I
cannot doubt that they already existed in the Miocene Austro-Columbian
province.
Nor is it less probable that the characteristic types of Australian
Mammalia were already developed in that region in Miocene times.
But Austro-Columbia presents difficulties from which Australia is
free; _Camelidae_ and _Tapiridae_ are now indigenous in South America
as they are in Arctogaea; and, among the Pliocene Austro-Columbian
mammals, the Austro-Columbian genera _Equus_, _Mastodon_, and
_Machairodus_ are numbered. Are these Postmiocene immigrants, or
Praemiocene natives?
Still more perplexing are the strange and interesting forms _Toxodon_,
_Macrauchenia_, _Typotherium_, and a new Anoplotherioid mammal
(_Homalodotherium_) which Dr. Cunningham sent over to me some time ago
from Patagonia. I confess I am strongly inclined to surmise that these
last, at any rate, are remnants of the population of Austro-Columbia
before the Miocene epoch, and were not derived from Arctogaea by way
of the north and east.
The fact that this immense fauna of Miocene Arctogaea is now fully
and richly represented only in India and in South Africa, while it
is shrunk and depauperized in North Asia, Europe, and North America,
becomes at once intelligible, if we suppose that India and South
Africa had but a scanty mammalian population before the Miocene
immigration, while the conditions were highly favourable to the new
comers. It is to be supposed that these new regions offered themselves
to the Miocene Ungulates, as South America and Australia offered
themselves to the cattle, sheep, and horses of modern colonists. But,
after these great areas were thus peopled, came the Glacial epoch,
during which the excessive cold, to say nothing of depression and
ice-covering, must have almost depopulated all the northern parts of
Arctogaea, destroying all the higher mammalian forms, except those
which, like the Elephant and Rhinoceros, could adjust their coats to
the altered conditions. Even these must have been driven away from the
greater part of the area; only those Miocene mammals which had passed
into Hindostan and into South Africa would escape decimation by such
changes in the physical geography of Arctogaea. And when the northern
hemisphere passed into its present condition, these lost tribes of the
Miocene Fauna were hemmed by the Himalayas, the Sahara, the Red Sea,
and the Arabian deserts, within their present boundaries. Now, on the
hypothesis of evolution, there is no sort of difficulty in admitting
that the differences between the Miocene forms of the mammalian
Fauna and those which exist at present are the results of gradual
modification; and, since such differences in distribution as obtain
are readily explained by the changes which have taken place in the
physical geography of the world since the Miocene epoch, it is clear
that the result of the comparison of the Miocene and present Fauna is
distinctly in favour of evolution. Indeed I may go further. I may
say that the hypothesis of evolution explains the facts of Miocene,
Pliocene, and Recent distribution, and that no other supposition even
pretends to account for them. It is, indeed, a conceivable supposition
that every species of Rhinoceros and every species of Hyaena, in the
long succession of forms between the Miocene and the present species,
was separately constructed out of dust, or out of nothing, by
supernatural power; but until I receive distinct evidence of the fact,
I refuse to run the risk of insulting any sane man by supposing that
he seriously holds such a notion.
Let us now take a step further back in time, and inquire into the
relations between the Miocene Fauna and its predecessor of the Upper
Eocene formation.
Here it is to be regretted that our materials for forming a judgment
are nothing to be compared in point of extent or variety with those
which are yielded by the Miocene strata. However, what we do know
of this Upper Eocene Fauna of Europe gives sufficient positive
information to enable us to draw some tolerably safe inferences. It
has yielded representatives of _Insectivora_, of _Cheiroptera_,
of _Rodentia_, of _Carnivora_, of artiodactyle and perissodactyle
_Ungulata_, and of opossum-like Marsupials. No Australian type of
Marsupial has been discovered in the Upper Eocene strata, nor any
Edentate mammal. The genera (except perhaps in the case of some of the
_Insectivora_, _Cheiroptera_, and _Rodentia_) are different from those
of the Miocene epoch, but present a remarkable general similarity to
the Miocene and recent genera. In several cases, as I have already
shown, it has now been clearly made out that the relation between
the Eocene and Miocene forms is such that the Eocene form is the less
specialized; while its Miocene ally is more so, and the specialization
reaches its maximum in the recent forms of the same type.
So far as the Upper Eocene and the Miocene Mammalian Faunae are
comparable, their relations are such as in no way to oppose the
hypothesis that the older are the progenitors of the more recent
forms, while, in some cases, they distinctly favour that hypothesis.
The period in time and the changes in physical geography represented
by the nummulitic deposits are undoubtedly very great, while the
remains of Middle Eocene and Older Eocene Mammals are comparatively
few. The general facies of the Middle Eocene Fauna, however, is quite
that of the Upper. The Older Eocene pre-nummulitic mammalian Fauna
contains Bats, two genera of _Carnivora_, three genera of _Ungulata_
(probably all perissodactyle), and a didelphid Marsupial; all these
forms, except perhaps the Bat and the Opossum, belong to genera
which are not known to occur out of the Lower Eocene formation. The
_Coryphodon_ appears to have been allied to the Miocene and later
Tapirs, while _Pliolophus_, in its skull and dentition, curiously
partakes of both artiodactyle and perissodactyle characters; the third
trochanter upon its femur, and its three-toed hind foot, however,
appear definitely to fix its position in the latter division.
There is nothing, then, in what is known of the older Eocene mammals
of the Arctogaeal province to forbid the supposition that they stood
in an ancestral relation to those of the Calcaire Grossier and the
Gypsum of the Paris basin, and that our present fauna, therefore, is
directly derived from that which already existed in Arctogaea at the
commencement of the Tertiary period. But if we now cross the frontier
between the Cainozoic and the Mesozoic faunae, as they are preserved
within the Arctogaeal area, we meet with an astounding change, and
what appears to be a complete and unmistakable break in the line of
biological continuity.
Among the twelve or fourteen species of _Mammalia_ which are said to
have been found in the Purbecks, not one is a member of the orders
_Cheiroptera_, _Rodentia_, _Ungulata_, or _Carnivora_, which are so
well represented in the Tertiaries. No _Insectivora_ are certainly
known, nor any opossum-like Marsupials. Thus there is a vast negative
difference between the Cainozoic and the Mesozoic mammalian faunae
of Europe. But there is a still more important positive difference,
inasmuch as all these Mammalia appear to be Marsupials belonging to
Australian groups, and thus appertaining to a different distributional
province from the Eocene and Miocene marsupials, which are
Austro-Columbian. So far as the imperfect materials which exist enable
a judgment to be formed, the same law appears to have held good for
all the earlier Mesozoic _Mammalia_. Of the Stonesfield slate mammals,
one, _Amphitherium_, has a definitely Australian character; one,
_Phascolotherium_, may be either Dasyurid or Didelphine; of a third,
_Stereognathus_, nothing can at present be said. The two mammals of
the Trias, also, appear to belong to Australian groups.
Every one is aware of the many curious points of resemblance between
the marine fauna of the European Mesozoic rocks and that which now
exists in Australia. But if there was this Australian facies about
both the terrestrial and the marine faunae of Mesozoic Europe, and
if there is this unaccountable and immense break between the fauna
of Mesozoic and that of Tertiary Europe, is it not a very obvious
suggestion that, in the Mesozoic epoch, the Australian province
included Europe, and that the Arctogaeal province was contained within
other limits? The Arctogaeal province is at present enormous, while
the Australian is relatively small. Why should not these proportions
have been different during the Mesozoic epoch?
Thus I am led to think that by far the simplest and most rational
mode of accounting for the great change which took place in the living
inhabitants of the European area at the end of the Mesozoic epoch, is
the supposition that it arose from a vast alteration of the physical
geography of the globe; whereby an area long tenanted by Cainozoic
forms was brought into such relations with the European area that
migration from the one to the other became possible, and took place on
a great scale.
This supposition relieves us, at once, from the difficulty in which we
were left, some time ago, by the arguments which I used to demonstrate
the necessity of the existence of all the great types of the Eocene
epoch in some antecedent period.
It is this Mesozoic continent (which may well have lain in the
neighbourhood of what are now the shores of the North Pacific Ocean)
which I suppose to have been occupied by the Mesozoic _Monodelphia_;
and it is in this region that I conceive they must have gone through
the long series of changes by which they were specialized into the
forms which we refer to different orders. I think it very probable
that what is now South America may have received the characteristic
elements of its mammalian fauna during the Mesozoic epoch; and there
can be little doubt that the general nature of the change which took
place at the end of the Mesozoic epoch in Europe was the upheaval of
the eastern and northern regions of the Mesozoic sea-bottom into a
westward extension of the Mesozoic continent, over which the mammalian
fauna, by which it was already peopled, gradually spread. This
invasion of the land was prefaced by a previous invasion of the
Cretaceous sea by modern forms of mollusca and fish.
It is easy to imagine how an analogous change might come about in the
existing world. There is, at present, a great difference between the
fauna of the Polynesian Islands and that of the west coast of America.
The animals which are leaving their spoils in the deposits now forming
in these localities are widely different. Hence, if a gradual
shifting of the deep sea, which at present bars migration between the
easternmost of these islands and America, took place to the westward,
while the American side of the sea-bottom was gradually upheaved,
the palaeontologist of the future would find, over the Pacific area,
exactly such a change as I am supposing to have occurred in the
North-Atlantic area at the close of the Mesozoic period. An Australian
fauna would be found underlying an American fauna, and the transition
from the one to the other would be as abrupt as that between the Chalk
and lower Tertiaries; and as the drainage-area of the newly formed
extension of the American continent gave rise to rivers and lakes, the
mammals mired in their mud would differ from those of like deposits on
the Australian side, just as the Eocene mammals differ from those of
the Purbecks.
How do similar reasonings apply to the other great change of
life--that which took place at the end of the Palaeozoic period?
In the Triassic epoch, the distribution of the dry land and of
terrestrial vertebrate life appears to have been, generally, similar
to that which existed in the Mesozoic epoch; so that the Triassic
continents and their faunae seem to be related to the Mesozoic lands
and their faunae, just as those of the Miocene epoch are related to
those of the present day. In fact, as I have recently endeavoured
to prove to the Society, there was an Arctogaeal continent and an
Arctogaeal province of distribution in Triassic times as there is now;
and the _Sauropsida_ and _Marsupialia_ which constituted that
fauna were, I doubt not, the progenitors of the _Sauropsida_ and
_Marsupialia_ of the whole Mesozoic epoch.
Looking at the present terrestrial fauna of Australia, it appears to
me to be very probable that it is essentially a remnant of the
fauna of the Triassic, or even of an earlier, age[1]; in which
case Australia must at that time have been in continuity with the
Arctogaeal continent.
[Footnote 1: Since this Address was read, Mr. Krefft has sent us
news of the discovery in Australia of a fresh-water fish of strangely
Palaeozoic aspect, and apparently a Ganoid intermediate between
_Dipterus_ and _Lepidosiren_.]
But now comes the further inquiry. Where was the highly differentiated
Sauropsidan fauna of the Trias in Palaeozoic times? The supposition
that the Dinosaurian, Crocodilian, Dicynodontian, and Plesiosaurian
types were suddenly created at the end of the Permian epoch may
be dismissed, without further consideration, as a monstrous and
unwarranted assumption. The supposition that all these types were
rapidly differentiated out of _Lacertilia_, in the time represented by
the passage from the Palaeozoic to the Mesozoic formation, appears to
me to be hardly more credible, to say nothing of the indications of
the existence of Dinosaurian forms in the Permian rocks which have
already been obtained.
For my part, I entertain no sort of doubt that the Reptiles, Birds,
and Mammals of the Trias are the direct descendants of Reptiles,
Birds, and Mammals which existed in the latter part of the Palaeozoic
epoch, but not in any area of the present dry land which has yet been
explored by the geologist.
This may seem a bold assumption, but it will not appear unwarrantable
to those who reflect upon the very small extent of the earth's surface
which has hitherto exhibited the remains of the great Mammalian fauna
of the Eocene times. In this respect, the Permian land Vertebrate
fauna appears to me to be related to the Triassic much as the Eocene
is to the Miocene. Terrestrial reptiles have been found in Permian
rocks only in three localities; in some spots of France, and recently
of England, and over a more extensive area in Germany. Who can suppose
that the few fossils yet found in these regions give any sufficient
representation of the Permian fauna?
It may be said that the Carboniferous formations demonstrate the
existence of a vast extent of dry land in the present dry-land area,
and that the supposed terrestrial Palaeozoic Vertebrate Fauna ought to
have left its remains in the Coal-measures, especially as there is now
reason to believe that much of the coal was formed by the accumulation
of spores and sporangia on dry land. But if we consider the matter
more closely, I think that this apparent objection loses its force. It
is clear that, during the Carboniferous epoch, the vast area of land
which is now covered by Coal-measures must have been undergoing a
gradual depression. The dry land thus depressed must, therefore, have
existed, as such, before the Carboniferous epoch--in other words, in
Devonian times--and its terrestrial population may never have been
other than such as existed during the Devonian, or some previous
epoch, although much higher forms may have been developed elsewhere.
Again, let me say that I am making no gratuitous assumption of
inconceivable changes. It is clear that the enormous area of Polynesia
is, on the whole, an area over which depression has taken place to
an immense extent; consequently a great continent, or assemblage of
subcontinental masses of land, must have existed at some former time,
and that at a recent period, geologically speaking, in the area of
the Pacific. But if that continent had contained Mammals, some of
them must have remained to tell the tale; and as it is well known that
these islands have no indigenous _Mammalia_, it is safe to assume that
none existed. Thus, midway between Australia and South America, each
of which possesses an abundant and diversified mammalian fauna, a mass
of land, which may have been as large as both put together, must have
existed without a mammalian inhabitant. Suppose that the shores of
this great land were fringed, as those of tropical Australia are now,
with belts of mangroves, which would extend landwards on the one
side, and be buried beneath littoral deposits on the other side,
as depression went on; and great beds of mangrove lignite might
accumulate over the sinking land. Let upheaval of the whole now take
place, in such a manner as to bring the emerging land into continuity
with the South-American or Australian continent, and, in course of
time, it would be peopled by an extension of the fauna of one of these
two regions--just as I imagine the European Permian dry land to have
been peopled.
I see nothing whatever against the supposition that distributional
provinces of terrestrial life existed in the Devonian epoch, inasmuch
as M. Barrande has proved that they existed much earlier. I am aware
of no reason for doubting that, as regards the grades of terrestrial
life contained in them, one of these may have been related to another
as New Zealand is to Australia, or as Australia is to India, at the
present day. Analogy seems to me to be rather in favour of, than
against, the supposition that while only Ganoid fishes inhabited the
fresh waters of our Devonian land, _Amphibia_ and _Reptilia_, or even
higher forms, may have existed, though we have not yet found them. The
earliest Carboniferous _Amphibia_ now known, such as _Anthracosaurus_,
are so highly specialized that I can by no means conceive that they
have been developed out of piscine forms in the interval between the
Devonian and the Carboniferous periods, considerable as that is. And I
take refuge in one of two alternatives: either they existed in our own
area during the Devonian epoch and we have simply not yet found them;
or they formed part of the population of some other distributional
province of that day, and only entered our area by migration at the
end of the Devonian epoch. Whether _Reptilia_ and _Mammalia_ existed
along with them is to me, at present, a perfectly open question, which
is just as likely to receive an affirmative as a negative answer from
future inquirers.
Let me now gather together the threads of my argumentation into the
form of a connected hypothetical view of the manner in which the
distribution of living and extinct animals has been brought about.
I conceive that distinct provinces of the distribution of terrestrial
life have existed since the earliest period at which that life is
recorded, and possibly much earlier; and I suppose, with Mr. Darwin,
that the progress of modification of terrestrial forms is more rapid
in areas of elevation than in areas of depression. I take it to be
certain that Labyrinthodont _Amphibia_ existed in the distributional
province which included the dry land depressed during the
Carboniferous epoch; and I conceive that, in some other distributional
provinces of that day, which remained in the condition of stationary
or of increasing dry land, the various types of the terrestrial
_Sauropsida_ and of the _Mammalia_ were gradually developing.
The Permian epoch marks the commencement of a new movement of upheaval
in our area, which attained its maximum in the Triassic epoch, when
dry land existed in North America, Europe, Asia, and Africa, as it
does now. Into this great new continental area the Mammals, Birds, and
Reptiles developed during the Palaeozoic epoch spread, and formed the
great Triassic Arctogaeal province. But, at the end of the Triassic
period, the movement of depression recommenced in our area, though
it was doubtless balanced by elevation elsewhere; modification and
development, checked in the one province, went on in that "elsewhere;"
and the chief forms of Mammals, Birds, and Reptiles, as we know them,
were evolved and peopled the Mesozoic continent. I conceive Australia
to have become separated from the continent as early as the end of
the Triassic epoch, or not much later. The Mesozoic continent must, I
conceive, have lain to the east, about the shores of the North Pacific
and Indian Oceans; and I am inclined to believe that it continued
along the eastern side of the Pacific area to what is now the province
of Austro-Columbia, the characteristic fauna of which is probably a
remnant of the population of the latter part of this period.
Towards the latter part of the Mesozoic period the movement of
upheaval around the shores of the Atlantic once more recommenced,
and was very probably accompanied by a depression around those of the
Pacific. The Vertebrate fauna elaborated in the Mesozoic continent
moved westward and took possession of the new lands, which gradually
increased in extent up to, and in some directions after, the Miocene
epoch.
It is in favour of this hypothesis, I think, that it is consistent
with the persistence of a general uniformity in the positions of the
great masses of land and water. From the Devonian period, or earlier,
to the present day, the four great oceans, Atlantic, Pacific, Arctic,
and Antarctic, may have occupied their present positions, and only
their coasts and channels of communication have undergone an incessant
alteration. And, finally, the hypothesis I have put before you
requires no supposition that the rate of change in organic life has
been either greater or less in ancient times than it is now; nor
any assumption, either physical or biological, which has not its
justification in analogous phenomena of existing nature.
I have now only to discharge the last duty of my office, which is
to thank you, not only for the patient attention with which you have
listened to me so long to-day, but also for the uniform kindness with
which, for the past two years, you have rendered my endeavours
to perform the important, and often laborious, functions of your
President a pleasure instead of a burden.
X.
MR. DARWIN'S CRITICS.[1]
The gradual lapse of time has now separated us by more than a decade
from the date of the publication of the "Origin of Species"--and
whatever may be thought or said about Mr. Darwin's doctrines, or the
manner in which he has propounded them, this much is certain, that,
in a dozen years, the "Origin of Species" has worked as complete
a revolution in biological science as the "Principia" did in
astronomy--and it has done so, because, in the words of Helmholtz, it
contains "an essentially new creative thought."[2]
[Footnote 1: 1. "Contributions to the Theory of Natural Selection."
By A.R. Wallace. 1870.--2. "The Genesis of Species." By St. George
Mivart, F.R.S. Second Edition. 1871.--3. "Darwin's Descent of Man."
_Quarterly Review_, July 1871.]
[Footnote 2: Helmholtz: "Ueber das Ziel und die Fortschritte der
Naturwissenschaft." Eroeffnungsrede fuer die Naturforscherversammlung zu
Innsbruck. 1869.]
And as time has slipped by, a happy change has come over Mr. Darwin's
critics. The mixture of ignorance and insolence which, at first,
characterized a large proportion of the attacks with which he
was assailed, is no longer the sad distinction of anti-Darwinian
criticism. Instead of abusive nonsense, which merely discredited its
writers, we read essays, which are, at worst, more or less intelligent
and appreciative; while, sometimes, like that which appeared in the
_North British Review_ for 1867, they have a real and permanent value.
The several publications of Mr. Wallace and Mr. Mivart contain
discussions of some of Mr. Darwin's views, which are worthy of
particular attention, not only on account of the acknowledged
scientific competence of these writers, but because they exhibit an
attention to those philosophical questions which underlie all physical
science, which is as rare as it is needful. And the same may be said
of an article in the _Quarterly Review_ for July 1871, the comparison
of which with an article in the same Review for July 1860, is perhaps
the best evidence which can be brought forward of the change which has
taken place in public opinion on "Darwinism."
The Quarterly Reviewer admits "the certainty of the action of natural
selection" (p. 49); and further allows that there is an _a priori_
probability in favour of the evolution of man from some lower animal
form, if these lower animal forms themselves have arisen by evolution.
Mr. Wallace and Mr. Mivart go much further than this. They are as
stout believers in evolution as Mr. Darwin himself; but Mr. Wallace
denies that man can have been evolved from a lower animal by that
process of natural selection which he, with Mr. Darwin, holds to have
been sufficient for the evolution of all animals below man; while
Mr. Mivart, admitting that natural selection has been one of the
conditions of the evolution of the animals below man, maintains that
natural selection must, even in their case, have been supplemented by
"some other cause"--of the nature of which, unfortunately, he does
not give us any idea. Thus Mr. Mivart is less of a Darwinian than Mr.
Wallace, for he has less faith in the power of natural selection. But
he is more of an evolutionist than Mr. Wallace, because Mr. Wallace
thinks it necessary to call in an intelligent agent--a sort of
supernatural Sir John Sebright--to produce even the animal frame of
man; while Mr. Mivart requires no Divine assistance till he comes to
man's soul.
Thus there is a considerable divergence between Mr. Wallace and Mr.
Mivart. On the other hand, there are some curious similarities between
Mr. Mivart and the Quarterly Reviewer, and these are sometimes so
close, that, if Mr. Mivart thought it worth while, I think he
might make out a good case of plagiarism against the Reviewer, who
studiously abstains from quoting him.
Both the Reviewer and Mr. Mivart reproach Mr. Darwin with being, "like
so many other physicists," entangled in a radically false metaphysical
system, and with setting at nought the first principles of both
philosophy and religion. Both enlarge upon the necessity of a sound
philosophical basis, and both, I venture to add, make a conspicuous
exhibition of its absence. The Quarterly Reviewer believes that man
"differs more from an elephant or a gorilla than do these from the
dust of the earth on which they tread," and Mr. Mivart has expressed
the opinion that there is more difference between man and an ape than
there is between an ape and a piece of granite.[1]
[Footnote 1: See the _Tablet_ for March 11, 1871.]
And even when Mr. Mivart (p. 86) trips in a matter of anatomy, and
creates a difficulty for Mr. Darwin out of a supposed close similarity
between the eyes of fishes and cephalopods, which (as Gegenbaur and
others have clearly shown) does not exist, the Quarterly Reviewer
adopts the argument without hesitation (p. 66).
There is another important point, however, in which it is hard to say
whether Mr. Mivart diverges from the Quarterly Reviewer or not.
The Reviewer declares that Mr. Darwin has, "with needless opposition,
set at nought the first principles of both philosophy and religion"
(p. 90).
It looks, at first, as if this meant, that Mr. Darwin's views being
false, the opposition to "religion" which flows from them must be
needless. But I suspect this is not the right view of the meaning of
the passage, as Mr. Mivart, from whom the Quarterly Reviewer plainly
draws so much inspiration, tells us that "the consequences which have
been drawn from evolution, whether exclusively Darwinian or not, to
the prejudice of religion, by no means follow from it, and are in fact
illegitimate" (p. 5).
I may assume, then, that the Quarterly Reviewer and Mr. Mivart admit
that there is no necessary opposition between "evolution, whether
exclusively Darwinian or not," and religion. But then, what do they
mean by this last much-abused term? On this point the Quarterly
Reviewer is silent. Mr. Mivart, on the contrary, is perfectly
explicit, and the whole tenor of his remarks leaves no doubt that by
"religion" he means theology; and by theology, that particular variety
of the great Proteus, which is expounded by the doctors of the Roman
Catholic Church, and held by the members of that religious community
to be the sole form of absolute truth and of saving faith.
According to Mr. Mivart, the greatest and most orthodox authorities
upon matters of Catholic doctrine agree in distinctly asserting
"derivative creation" or evolution; "and thus their teachings
harmonize with all that modern science can possibly require" (p. 305).
I confess that this bold assertion interested me more than anything
else in Mr. Mivart's book. What little knowledge I possessed of
Catholic doctrine, and of the influence exerted by Catholic authority
in former times, had not led me to expect that modern science was
likely to find a warm welcome within the pale of the greatest and most
consistent of theological organizations.
And my astonishment reached its climax when I found Mr. Mivart citing
Father Suarez as his chief witness in favour of the scientific freedom
enjoyed by Catholics--the popular repute of that learned theologian
and subtle casuist not being such as to make his works a likely place
of refuge for liberality of thought. But in these days, when Judas
Iscariot and Robespierre, Henry VIII. and Catiline, have all been
shown to be men of admirable virtue, far in advance of their age,
and consequently the victims of vulgar prejudice, it was obviously
possible that Jesuit Suarez might be in like case. And, spurred by Mr.
Mivart's unhesitating declaration, I hastened to acquaint myself
with such of the works of the great Catholic divine as bore upon
the question, hoping, not merely to acquaint myself with the true
teachings of the infallible Church, and free myself of an unjust
prejudice; but, haply, to enable myself, at a pinch, to put some
Protestant bibliolater to shame, by the bright example of Catholic
freedom from the trammels of verbal inspiration.
I regret to say that my anticipations have been cruelly disappointed.
But the extent to which my hopes have been crushed can only be fully
appreciated by citing, in the first place, those passages of Mr.
Mivart's work by which they were excited. In his introductory chapter
I find the following passages:--
"The prevalence of this theory [of evolution] need alarm no one, for
it is, without any doubt, perfectly consistent with the strictest and
most orthodox Christian[1] theology" (p. 5).
[Footnote 1: It should be observed that Mr. Mivart employs the term
"Christian" as if it were the equivalent of "Catholic."]
"Mr. Darwin and others may perhaps be excused if they have not devoted
much time to the study of Christian philosophy; but they have no right
to assume or accept without careful examination, as an unquestioned
fact, that in that philosophy there is a necessary antagonism between
the two ideas 'creation' and 'evolution,' as applied to organic forms.
"It is notorious and patent to all who choose to seek, that many
distinguished Christian thinkers have accepted, and do accept, both
ideas, i.e. both 'creation' and 'evolution.'
"As much as ten years ago an eminently Christian writer observed: 'The
creationist theory does not necessitate the perpetual search after
manifestations of miraculous power and perpetual "catastrophes."
Creation is not a miraculous interference with the laws of nature, but
the very institution of those laws. Law and regularity, not arbitrary
intervention, was the patristic ideal of creation. With this notion
they admitted, without difficulty, the most surprising origin of
living creatures, provided it took place by _law_. They held that
when God said, "Let the waters produce," "Let the earth produce," He
conferred forces on the elements of earth and water, which enabled
them naturally to produce the various species of organic beings. This
power, they thought, remains attached to the elements throughout all
time.' The same writer quotes St. Augustin and St. Thomas Aquinas,
to the effect that, 'in the institution of nature, we do not look for
miracles, but for the laws of nature,' And, again, St. Basil speaks
of the continued operation of natural laws in the production of all
organisms.
"So much for the writers of early and mediaeval times. As to the
present day, the author can confidently affirm that there are many
as well versed in theology as Mr. Darwin is in his own department
of natural knowledge, who would not be disturbed by the thorough
demonstration of his theory. Nay, they would not even be in the least
painfully affected at witnessing the generation of animals of complex
organization by the skilful artificial arrangement of natural forces,
and the production, in the future, of a fish by means analogous to
those by which we now produce urea.
"And this because they know that the possibility of such phenomena,
though by no means actually foreseen, has yet been fully provided
for in the old philosophy centuries before Darwin, or even centuries
before Bacon, and that their place in the system can be at once
assigned them without even disturbing its order or marring its
harmony.
"Moreover, the old tradition in this respect has never been abandoned,
however much it may have been ignored or neglected by some modern
writers. In proof of this, it may be observed that perhaps no
post-mediaeval theologian has a wider reception amongst Christians
throughout the world than Suarez, who has a separate section[1] in
opposition to those who maintain the distinct creation of the various
kinds--or substantial forms--of organic life" (pp. 19-21).
[Footnote 1: Suarez; Metaphysica. Edition Vives. Paris, 1868, vol. i.
Disput. xv. Sec. 2.]
Still more distinctly does Mr. Mivart express himself, in the same
sense, in his last chapter, entitled "Theology and Evolution" (pp.
302-5).
"It appears, then, that Christian thinkers are perfectly free to
accept the general evolution theory. But are there any theological
authorities to justify this view of the matter?
"Now, considering how extremely recent are these biological
speculations, it might hardly be expected _a priori_ that writers of
earlier ages should have given expression to doctrines harmonizing
in any degree with such very modern views; nevertheless, this is
certainly the case, and it would be easy to give numerous examples.
It will be better, however, to cite one or two authorities of weight.
Perhaps no writer of the earlier Christian ages could be quoted whose
authority is more generally recognized than that of St. Augustin. The
same may be said of the mediaeval period for St. Thomas Aquinas: and
since the movement of Luther, Suarez may be taken as an authority,
widely venerated, and one whose orthodoxy has never been questioned.
"It must be borne in mind that for a considerable time even after
the last of these writers no one had disputed the generally received
belief as to the small age of the world, or at least of the kinds of
animals and plants inhabiting it. It becomes, therefore, much more
striking if views formed under such a condition of opinion are found
to harmonize with modern ideas concerning 'Creation' and organic Life.
"Now St. Augustin insists in a very remarkable manner on the merely
derivative sense in which God's creation of organic forms is to
be understood; that is, that God created them by conferring on the
material world the power to evolve them under suitable conditions."
Mr. Mivart then cites certain passages from St. Augustin, St. Thomas
Aquinas, and Cornelius a Lapide, and finally adds:--
"As to Suarez, it will be enough to refer to Disp. xv. sec.
2, No. 9, p. 508, t.i. edition Vives, Paris; also Nos. 13--15.
Many other references to the same effect could easily be
given, but these may suffice.
"It is then evident that ancient and most venerable
theological authorities distinctly assert _derivative_
creation, and thus their teachings harmonize with all that
modern science can possibly require."
It will be observed that Mr. Mivart refers solely to Suarez's
fifteenth Disputation, though he adds, "Many other references to the
same effect could easily be given." I shall look anxiously for these
references in the third edition of the "Genesis of Species." For the
present, all I can say is, that I have sought in vain, either in
the fifteenth Disputation, or elsewhere, for any passage in Suarez's
writings which, in the slightest degree, bears out Mr. Mivart's views
as to his opinions.[1]
[Footnote 1: The edition of Suarez's "Disputationes" from which the
following citations are given, is Birckmann's, in two volumes folio,
and is dated 1630.]
The title of this fifteenth Disputation is "De causa formali
substantiali," and the second section of that Disputation (to which
Mr. Mivart refers) is headed, "Quomodo possit forma substantialis
fieri in materia et ex materia?"
The problem which Suarez discusses in this place may be popularly
stated thus: According to the scholastic philosophy every natural body
has two components--the one its "matter" (_materia prima_), the other
its "substantial form" (_forma substantialis_). Of these the matter
is everywhere the same, the matter of one body being indistinguishable
from the matter of any other body. That which differentiates any one
natural body from all others is its substantial form, which inheres
in the matter of that body, as the human soul inheres in the matter
of the frame of man, and is the source of all the activities and other
properties of the body.
Thus, says Suarez, if water is heated, and the source of heat is then
removed, it cools again. The reason of this is that there is a certain
"_intimius principium_" in the water, which brings it back to the
cool condition when the external impediment to the existence of that
condition is removed. This _intimius principium_, is the "substantial
form" of the water. And the substantial form of the water is not only
the cause (_radix_) of the coolness of the water, but also of its
moisture, of its density, and of all its other properties.
It will thus be seen that "substantial forms" play nearly the same
part in the scholastic philosophy as "forces" do in modern science;
the general tendency of modern thought being to conceive all bodies as
resolvable into material particles and forces, in virtue of which last
these particles assume those dispositions and exercise those powers
which are characteristic of each particular kind of matter.
But the Schoolmen distinguished two kinds of substantial forms,
the one spiritual and the other material. The former division is
represented by the human soul, the _anima rationalis_; and they affirm
as a matter, not merely of reason, but of faith, that every human soul
is created out of nothing, and by this act of creation is endowed with
the power of existing for all eternity, apart from the _materia
prima_ of which the corporeal frame of man is composed. And the _anima
rationalis_, once united with the _materia prima_ of the body,
becomes its substantial form, and is the source of all the powers and
faculties of man--of all the vital and sensitive phenomena which he
exhibits--just as the substantial form of water is the source of all
its qualities.
The "material substantial forms" are those which inform all other
natural bodies except that of man; and the object of Suarez in the
present Disputation, is to show that the axiom "_ex nihilo nihil
fit_," though not true of the substantial form of man, is true of the
substantial forms of all other bodies, the endless mutations of which
constitute the ordinary course of nature. The origin of the difficulty
which he discusses is easily comprehensible. Suppose a piece of bright
iron to be exposed to the air. The existence of the iron depends on
the presence within it of a substantial form, which is the cause of
its properties, e.g. brightness, hardness, weight. But, by degrees,
the iron becomes converted into a mass of rust, which is dull, and
soft, and light, and, in all other respects, is quite different from
the iron. As, in the scholastic view, this difference is due to the
rust being informed by a new substantial form, the grave problem
arises, how did this new substantial form come into being? Has it been
created? or has it arisen by the power of natural causation? If the
former hypothesis is correct, then the axiom, "_ex nihilo nihil fit_,"
is false, even in relation to the ordinary course of nature, seeing
that such mutations of matter as imply the continual origin of new
substantial forms are occurring every moment. But the harmonization of
Aristotle with theology was as dear to the Schoolmen, as the smoothing
down the differences between Moses and science is to our Broad
Churchmen, and they were proportionably unwilling to contradict one
of Aristotle's fundamental propositions. Nor was their objection to
flying in the face of the Stagirite likely to be lessened by the fact
that such flight landed them in flat Pantheism.
So Father Suarez fights stoutly for the second hypothesis; and I quote
the principal part of his argumentation as an exquisite specimen of
that speech which is a "darkening of counsel."
"13. Secundo de omnibus aliis formis substantialibus (sc.
materialibus) dicendum est non fieri proprie ex nihilo, sed
ex potentia praejacentis materiae educi: ideoque in effectione
harum formarum nil fieri contra illud axioma, _Ex nihila
nihil fit_, si recte intelligatur. Haec assertio sumitur ex
Aristotele 1. Physicorum per totum et libro 7. Metaphyss.
et ex aliis authoribus, quos statim referam. Et declaratur
breviter, nam fieri ex nihilo duo dicit, unum est fieri
absolute et simpliciter, aliud est quod talis effectio fit ex
nihilo. Primum proprie dicitur de re subsistente, quia ejus
est fieri, cujus est esse: id autem proprie quod subsistit et
habet esse; nam quod alteri adjacet, potius est quo aliud est.
Ex hac ergo parte, formae substantiales materiales non fiunt
ex nihilo, quia proprie non fiunt. Atque hanc rationem reddit
Divus Thomas I parte, quaestione 45, articulo 8, et quaestione
90, articulo 2, et ex dicendis magis explicabitur. Sumendo
ergo ipsum _fieri_ in hac proprietate et rigore, sic fieri
ex nihilo est fieri secundum se totum, id est nulla sui parte
praesupposita, ex quo fiat. Et hac ratione res naturales
dum de novo fiunt, non fiunt ex nihilo, quia fiunt ex
praesupposita materia, ex qua componuntur, et ita non fiunt,
secundum se totae, sed secundum aliquid sui. Formae autem
harum rerum, quamvis revera totam suam entitatem de novo
accipiant, quam antea non habebant, quia vero ipsae non fiunt,
ut dictum est, ideo neque ex nihilo fiunt. Attamen, quia
latiori modo sumendo verbum illud _fieri_ negari non potest:
quia forma facta sit, eo modo quo nunc est, et antea non erat,
ut etiam probat ratio dubitandi posita in principio sectionis,
ideo addendum est, sumpto _fieri_ in hac amplitudine, fieri
ex nihilo non tamen negare habitudinem materialis causea
intrinsece componentis id quod fit, sed etiam habitudinem
causae materialis per se causantis et sustentantis formam quae
fit, seu confit. Diximus enim in superioribus materiam et esse
causam compositi et formae dependentis ab ilia: ut res ergo
dicatur ex nihilo fieri uterque modus causalitatis negari
debet; et eodem sensu accipiendum est illud axioma, ut
sit verum: _Ex nihilo nihil fit_, scilicet virtute agentis
naturalis et finiti nihil fieri, nisi ex praesupposito
subjecto per se concurrente, et ad compositum et ad formam,
si utrumque suo modo ab eodem agente fiat. Ex his ergo recte
concluditur, formas substantiales materiales non fieri ex
nihilo, quia fiunt ex materia, quae in suo genere per se
concurrit, et influit ad esse, et fieri talium formarum;
quia, sicut esse non possunt nisi affixae materiae, a qua
sustententur in esse: ita nec fieri possunt, nisi earum
effectio et penetratio in eadem materia sustentetur. Et haec
est propria et per se differentia inter effectionem ex nihilo,
et ex aliquo, propter quam, ut infra ostendemus, prior modus
effciendi superat vim finitam naturaliam agentium, non vero
posterior.
"14. Ex his etiam constat, proprie de his formis dici non
creari, sed educi de potentia materiae."[1]
[Footnote 1: Suarez, _loc. cit_. Disput. xv. Sec. ii.]
If I may venture to interpret these hard sayings, Suarez conceives
that the evolution of substantial forms in the ordinary course of
nature, is conditioned not only by the existence of the _materia
prima_, but also by a certain "concurrence and influence" which
that _materia_ exerts; and every new substantial form being thus
conditioned, and in part, at any rate, caused, by a pre-existing
something, cannot be said to be created out of nothing.
But as the whole tenor of the context shows, Suarez applies this
argumentation merely to the evolution of material substantial forms
in the ordinary course of nature. How the substantial forms of animals
and plants primarily originated, is a question to which, so far as
I am able to discover, he does not so much as allude in his
"Metaphysical Disputations." Nor was there any necessity that he
should do so, inasmuch as he has devoted a separate treatise of
considerable bulk to the discussion of all the problems which arise
out of the account of the Creation which is given in the Book of
Genesis. And it is a matter of wonderment to me that Mr. Mivart, who
somewhat sharply reproves "Mr. Darwin and others" for not acquainting
themselves with the true teachings of his Church, should allow
himself to be indebted to a heretic like myself for a knowledge of
the existence of that "Tractatus de opere sex Dierum," I in which
the learned Father, of whom he justly speaks, as "an authority widely
venerated, and whose orthodoxy has never been questioned," directly
opposes all those opinions, for which Mr. Mivart claims the shelter of
his authority.
In the tenth and eleventh chapters of the first book of this treatise,
Suarez inquires in what sense the word "day," as employed in the first
chapter of Genesis, is to be taken. He discusses the views of Philo
and of Augustin on this question, and rejects them. He suggests that
the approval of their allegorizing interpretations by St. Thomas
Aquinas, merely arose out of St. Thomas's modesty, and his desire not
to seem openly to controvert St. Augustin--"voluisse Divus Thomas pro
sua modestia subterfugere vim argumenti potius quam aperte Augustinum
inconstantiae arguere."
Finally, Suarez decides that the writer of Genesis meant that the
term "day" should be taken in its natural sense; and he winds up
the discussion with the very just and natural remark that "it is
not probable that God, in inspiring Moses to write a history of the
Creation which was to be believed by ordinary people, would have made
him use language, the true meaning of which it is hard to discover,
and still harder to believe."[1]
[Footnote 1: "Tractatus de opere sex Dierum, seu de Universi
Creatione, quatenus sex diebus perfecta esse, in libro Genesis cap. i.
refertur, et praesertim de productioue hominis in statu innocentiae."
Ed. Birckmann, 1622.]
And in chapter xii. 3, Suarez further observes:--
"Ratio enim retinendi veram significationem diei naturalis est
illa communis, quod verba Scripturae non sunt ad metaphoras
transferenda, nisi vel necessitas cogit, vel ex ipsa scriptura
constet, et maxime in historica narratione et ad instructionem
fidei pertinente: sed haec ratio non minus cogit ad
intelligendum proprie dierum numerum, quam diei qualitatem,
QUIA NON MINUS UNO MODO QUAM ALIO DESTRUITUR SINCERITAS,
IMO ET VERITAS HISTORIAE. Secundo hoc valde confirmant alia
Scripturae loca, in quibus hi sex dies tanquam veri, et inter
se distincti commemorantur, ut Exod. 20 dicitur, _Sex diebus
operabis et facies omnia opera tua, septimo autem die Sabbatum
Domini Dei tui est_. Et infra: _Sex enim diebus fecit Dominus
caelum et terram et mare et omnia quae in eis sunt_, et idem
repetitur in cap. 31. In quibus locis sermonis proprietas
colligi potest tum ex aequiparatione, nam cum dicitur: _sex
diebus operabis_, propriissime intelligitur: tum quia non est
verisimile, potuisse populum intelligere verba illa in alio
sensu, et e contrario incredibile est, Deum in suis praeceptis
tradendis illis verbis ad populum fuisse loquutum, quibus
deciperetur, falsum sensum concipiendo, si Deus non per sex
veros dies opera sua fecisset."
These passages leave no doubt that this great doctor of the Catholic
Church, of unchallenged authority and unspotted orthodoxy, not only
declares it to be Catholic doctrine that the work of creation took
place in the space of six natural days; but that he warmly repudiates,
as inconsistent with our knowledge of the Divine attributes, the
supposition that the language which Catholic faith requires the
believer to hold that God inspired, was used in any other sense than
that which He knew it would convey to the minds of those to whom it
was addressed.
And I think that in this repudiation Father Suarez will have the
sympathy of every man of common uprightness, to whom it is certainly
"incredible" that the Almighty should have acted in a manner which He
would esteem dishonest and base in a man.
But the belief that the universe was created in six natural days is
hopelessly inconsistent with the doctrine of evolution, in so far as
it applies to the stars and planetary bodies; and it can be made to
agree with a belief in the evolution of living beings only by the
supposition that the plants and animals, which are said to have been
created on the third, fifth, and six days, were merely the primordial
forms, or rudiments, out of which existing plants and animals have
been evolved; so that, on these days, plants and animals were not
created actually, but only potentially.
The latter view is that held by Mr. Mivart, who follows St. Augustin,
and implies that he has the sanction of Suarez. But, in point of fact,
the latter great light of orthodoxy takes no small pains to give the
most explicit and direct contradiction to all such imaginations, as
the following passages prove. In the first place, as regards plants,
Suarez discusses the problem:--
"_Quomodo herba virens et caetera vegetabilia hoc [tertio] die
fuerint producta._[1]
[Footnote 1: "Propter haec ergo sententia illa Augustini et
propter nimiam obscuritatem et subtilitatem ejus difficilis
creditu est: quia verisimile non est Deum inspirasse Moysi,
ut historiam de creatione mundi ad fidem totius populi adeo
necessariam per nomina dierum explicaret, quorum significatio
vix inveniri et difficillime ab aliquo credi posset." _(Loc.
cit._ Lib. I. cap. xi. 42.)]
"Praecipua enim difficultas hic est, quam attingit Div. Thomas
I, par. qu. 69, art. 2, an haec productio plantarum hoc die
facta intelligenda sit de productione ipsarum in proprio esse
actuali et formali (ut sic rem explicerem) vel de productione
tantum in semine et in potentia. Nam Divus Augustinus libro
quinto Genes, ad liter, cap. 4 et 5 et libro 8, cap. 3,
posteriorem partem tradit, dicens, terram in hoc die accepisse
virtutem germinandi omnia vegetabilia quasi concepto omnium
illorum semine, non tamen statim vegetabilia omnia produxisse.
Quod primo suadet verbis illis capitis secundi. _In die quo
fecit Deus coelum et terram et omne virgultum agri priusquam,
germinaret_. Quomodo enim potuerunt virgulta fieri antequam
terra germinaret nisi quia causaliter prius et quasi in
radice, seu in semine facta sunt, et postea in actu producta?
Secundo confirmari potest, quia verbum illud _germinet terra_
optime exponitur potestative ut sic dicam, id est, accipiat
terra vim germinandi. Sicut in eodem capite dicitur _crescite
et multiplicamini_. Tertio potest confirmari, quia actualis
productio vegetabilium non tarn ad opus creationis, quam ad
opus propagationis pertinet, quod postea factum est. Et hanc
sententiam sequitur Eucherius lib. 1, in Gen. cap. 11, et illi
faveat Glossa, interli. Hugo. et Lyran. dum verbum _germinet_
dicto modo exponunt. NIHILOMINUS CONTRARIA SENTENTIA TENENDA
EST: SCILICET, PRODUXISSE DEUM HOC DIE HERBAM, ARBORES, ET
ALIA VEGETABILIA ACTU IN PROPRIA SPECIE ET NATURA. Haec est
communis sententia Patrum.--Basil, homil. 5; Exaemer. Ambros.
lib. 3; Exaemer. cap. 8,11, et 16; Chrysost, homil. 5 in Gen.
Damascene, lib. 2 de Fid. cap. 10; Theodor. Cyrilli. Bedae,
Glossae ordinariae et aliorum in Gen. Et idem sentit Divus
Thomas, _supra_, solvens argumenta Augustini, quamvis propter
reverentiam ejus quasi problematice semper procedat. Denique
idem sentiunt omnes qui in his operibus veram successionem et
temporalem distinctionem agnoscant."
Secondly, with respect to animals, Suarez is no less decided:--
_De animalium ratione carentium productione quinto et sexto
die facta._[1]
"32. Primo ergo nobis certum sit haec animantia non in virtute
tantum aut in semine, sed actu, et in seipsis, facta fuisse
his diebus in quibus facta narrantur. Quanquam Augustinus
lib. 3, Gen. ad liter, cap. 5 in sua persistens sententia
contrarium sentire videatur."
[Footnote 1: _Loc. cit._ Lib. II. cap. vii. et viii. 1, 32, 35.]
But Suarez proceeds to refute Augustin's opinions at great length, and
his final judgment may be gathered from the following passage:--
"35. Tertio dicendum est, haec animalia omnia his diebus
producta esse, IN PERFECTO STATU, IN SINGULIS INDIVIDUIS, SEU
SPECIEBUS SUIS, JUXTA UNIUSCUJUSQUE NATURAM.... ITAQUE FUERUNT
OMNIA CREATA INTEGRA ET OMNIBUS SUIS MEMBRIS PERFECTA."
As regards the creation of animals and plants, therefore, it is clear
that Suarez, so far from "distinctly asserting derivative creation,"
denies it as distinctly and positively as he can; that he is at much
pains to refute St. Augustin's opinions; that he does not hesitate to
regard the faint acquiescence of St. Thomas Aquinas in the views of
his brother saint as a kindly subterfuge on the part of Divus Thomas;
and that he affirms his own view to be that which is supported by the
authority of the Fathers of the Church. So that, when Mr. Mivart tells
us that Catholic theology is in harmony with all that modern science
can possibly require; that "to the general theory of evolution, and
to the special Darwinian form of it, no exception ... need be taken on
the ground of orthodoxy;" and that "law and regularity, not arbitrary
intervention, was the Patristic ideal of creation," we have to choose
between his dictum, as a theologian, and that of a great light of
his Church, whom he himself declares to be "widely venerated as an
authority, and whose orthodoxy has never been questioned."
But Mr. Mivart does not hesitate to push his attempt to harmonize
science with Catholic orthodoxy to its utmost limit; and, while
assuming that the soul of man "arises from immediate and direct
creation," he supposes that his body was "formed at first (as now
in each separate individual) by derivative, or secondary creation,
through natural laws" (p. 331).
This means, I presume, that an animal, having the corporeal form and
bodily powers of man, may have been developed out of some lower form
of life by a process of evolution; and that, after this anthropoid
animal had existed for a longer or shorter time, God made a soul by
direct creation, and put it into the manlike body, which, heretofore,
had been devoid of that _anima rationalis_, which is supposed to be
man's distinctive character.
This hypothesis is incapable of either proof or disproof, and
therefore may be true; but if Suarez is any authority, it is not
Catholic doctrine. "Nulla est in homine forma educta de potentia
materiae,"[1] is a dictum which is absolutely inconsistent with the
doctrine of the natural evolution of any vital manifestation of the
human body.
[Footnote 1: Disput. xv. Sec. x. No. 27.]
Moreover, if man existed as an animal before he was provided with a
rational soul, he must, in accordance with the elementary requirements
of the philosophy in which Mr. Mivart delights, have possessed a
distinct sensitive and vegetative soul, or souls. Hence, when the
"breath of life" was breathed into the manlike animal's nostrils,
he must have already been a living and feeling creature. But Suarez
particularly discusses this point, and not only rejects Mr. Mivart's
view, but adopts language of very theological strength regarding it.
"Possent praeterea his adjungi argumenta theologica, ut est
illud quod sumitur ex illis verbis Genes. 2. _Formavit Deus
hominem ex limo terrae et inspiravit in faciem ejus spiraculum
vitae et factus est homo in animam viventem_: ille enim
spiritus, quam Deus spiravit, anima rationalis fuit, et PER
EADEM FACTUS EST HOMO VIVENS, ET CONSEQUENTER, ETIAM SENTIENS.
"Aliud est ex VIII. Synodo Generali quae est
Constantinopolitana IV. can. 11, qui sic habet. _Apparet
quosdam in tantum impietatis venisse ut homines duas animas
habere dogmatizent: talis igitur impietatis inventores et
similes sapientes, cum Vetus et Novum Testamentum_ _omnesque
Ecclesiae patres unam animam rationalem hominem habere
asseverent, Sancta et universalis Synodus anathematizat_."[1]
[Footnote 1: Disput. xv. "De causa formali substantiali," Sec. x. No.
24.]
Moreover, if the animal nature of man was the result of evolution, so
must that of woman have been. But the Catholic doctrine, according to
Suarez, is that woman was, in the strictest and most literal sense of
the words, made out of the rib of man.
"Nihilominus sententia Catholica est, verba illa Scripturae
esse ad literam intelligenda. AC PROINDE VERE, AC REALITER,
TULISSE DEUM COSTAM ADAE, ET, EX ILLA, CORPUS EVAE
FORMASSE."[1]
[Footnote 1: "Tractatus de Opere," Lib. III. "De hominis creatione,"
cap. ii. No. 3.]
Nor is there any escape in the supposition that some woman existed
before Eve, after the fashion of the Lilith of the rabbis;
since Suarez qualifies that notion, along with some other Judaic
imaginations, as simply "damnabilis."[1]
[Footnote 1: Ibid. Lib. III. cap. iv. Nos. 8 and 9.]
After the perusal of the "Tractatus de Opere" it is, in fact,
impossible to admit that Suarez held any opinion respecting the origin
of species, except such as is consistent with the strictest and most
literal interpretation of the words of Genesis. For Suarez, it is
Catholic doctrine, that the world was made in six natural days. On the
first of these days the _materia prima_ was made out of nothing, to
receive afterwards those "substantial forms" which moulded it into
the universe of things; on the third day, the ancestors of all living
plants suddenly came into being, full-grown, perfect, and possessed of
all the properties which now distinguish them; while, on the fifth
and sixth days, the ancestors of all existing animals were similarly
caused to exist in their complete and perfect state, by the infusion
of their appropriate material substantial forms into the matter
which had already been created. Finally on the sixth day, the _anima
rationalis_--that rational and immortal substantial form which is
peculiar to man--was created out of nothing, and "breathed into" a
mass of matter which, till then, was mere dust of the earth, and so
man arose. But the species man was represented by a solitary male
individual, until the Creator took out one of his ribs and fashioned
it into a female.
This is the view of the "Genesis of Species," held by Suarez to be the
only one consistent with Catholic faith: it is because he holds this
view to be Catholic that he does not hesitate to declare St. Augustin
unsound, and St. Thomas Aquinas guilty of weakness, when the one
swerved from this view and the other tolerated the deviation. And,
until responsible Catholic authority--say, for example, the Archbishop
of Westminster--formally declares that Suarez was wrong, and that
Catholic priests are free to teach their flocks that the world was
_not_ made in six natural days, and that plants and animals were _not_
created in their perfect and complete state, but have been evolved by
natural processes through long ages from certain germs in which they
were potentially contained, I, for one, shall feel bound to believe
that the doctrines of Suarez are the only ones which are sanctioned
by Infallible Authority, as represented by the Holy Father and the
Catholic Church.
I need hardly add that they are as absolutely denied and repudiated by
Scientific Authority, as represented by Reason and Fact. The question
whether the earth and the immediate progenitors of its present living
population were made in six natural days or not, is no longer one upon
which two opinions can be held.
The fact that it did not so come into being stands upon as sound a
basis as any fact of history whatever. It is not true that existing
plants and animals came into being within three days of the creation
of the earth out of nothing, for it is certain that innumerable
generations of other plants and animals lived upon the earth before
its present population. And when, Sunday after Sunday, men who profess
to be our instructors in righteousness read out the statement, "In
six days the Lord made heaven and earth, the sea, and all that in them
is," in innumerable churches, they are either propagating what they
may easily know, and, therefore, are bound to know, to be falsities;
or, if they use the words in some non-natural sense, they fall below
the moral standard of the much-abused Jesuit.
Thus far the contradiction between Catholic verity and Scientific
verity is complete and absolute, quite independently of the truth or
falsehood of the doctrine of evolution. But, for those who hold the
doctrine of evolution, all the Catholic verities about the creation of
living beings must be no less false. For them, the assertion that
the progenitors of all existing plants were made on the third day, of
animals on the fifth and sixth days, in the forms they now present, is
simply false. Nor can they admit that man was made suddenly out of the
dust of the earth; while it would be an insult to ask an evolutionist
whether he credits the preposterous fable respecting the fabrication
of woman to which Suarez pins his faith. If Suarez has rightly stated
Catholic doctrine, then is evolution utter heresy. And such I believe
it to be. In addition to the truth of the doctrine of evolution,
indeed, one of its greatest merits in my eyes, is the fact that it
occupies a position of complete and irreconcilable antagonism to that
vigorous and consistent enemy of the highest intellectual, moral, and
social life of mankind--the Catholic Church. No doubt, Mr. Mivart,
like other putters of new wine into old bottles, is actuated by
motives which are worthy of respect, and even of sympathy; but his
attempt has met with the fate which the Scripture prophesies for all
such.
Catholic theology, like all theologies which are based upon the
assumption of the truth of the account of the origin of things given
in the Book of Genesis, being utterly irreconcilable with the doctrine
of evolution, the student of science, who is satisfied that the
evidence upon which the doctrine of evolution rests, is incomparably
stronger and better than that upon which the supposed authority of
the Book of Genesis rests, will not trouble himself further with these
theologies, but will confine his attention to such arguments against
the view he holds as are based upon purely scientific data--and
by scientific data I do not merely mean the truths of physical,
mathematical, or logical science, but those of moral and metaphysical
science. For, by science, I understand all knowledge which rests upon
evidence and reasoning of a like character to that which claims our
assent to ordinary scientific propositions. And if any one is able to
make good the assertion that his theology rests upon valid evidence
and sound reasoning, then it appears to me that such theology will
take its place as a part of science.
The present antagonism between theology and science does not arise
from any assumption by the men of science that all theology must
necessarily be excluded from science; but simply because they are
unable to allow that reason and morality have two weights and two
measures; and that the belief in a proposition, because authority
tells you it is true, or because you wish to believe it, which is a
high crime and misdemeanour when the subject matter of reasoning is
of one kind, becomes under the _alias_ of "faith" the greatest of all
virtues, when the subject matter of reasoning is of another kind.
The Bishop of Brechin said well the other day:--"Liberality in
religion--I do not mean tender and generous allowances for the
mistakes of others--is only unfaithfulness to truth."[1] And, with
the same qualification, I venture to paraphrase the Bishop's dictum:
"Ecclesiasticism in science is only unfaithfulness to truth."
[Footnote 1: Charge at the Diocesan Synod of Brechin. _Scotsman_,
Sept. 14, 1871.]
Elijah's great question, "Will you serve God or Baal? Choose ye," is
uttered audibly enough in the ears of every one of us as we come to
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