THE CLASSICAL TRADITION IN MODERN MORPHOLOGY
To write a history of contemporary movements from a purely objective
standpoint is well recognised to be an impossible task. It is difficult
for those in the stream to see where the current is carrying them: the
tendencies of the present will only become clear some twenty years in
the future.
I propose, therefore, in this concluding chapter to deal only with
certain characteristics of modern work on the problems of form which
seem to me to be derived directly from the older classical tradition of
Cuvier and von Baer.
The present time is essentially one of transition. Complete uncertainty
reigns as to the main principles of biology. Many of us think that the
materialistic and simplicist method has proved a complete failure, and
that the time has come to strike out on entirely different lines. Just
in what direction the new biology will grow out is hard to see at
present, so many divergent beginnings have been made--the materialistic
vitalism of Driesch, the profound intuitionalism of Bergson, the
psychological biology of Delpino, France, Pauly, A. Wagner and W.
Mackenzie. But if any of these are destined to give the future direction
to biology, they will in a measure only be bringing biology back to its
pre-materialistic tradition, the tradition of Aristotle, Cuvier, von
Baer and J. Mueller. It may well be that the intransigent materialism of
the 19th century is merely an episode, an aberration rather, in the
history of biology--an aberration brought about by the over-rapid
development of a materialistic and luxurious civilisation, in which
man's material means have outrun his mental and moral growth.
Two movements seem significant in the morphology of the last decade or
so of the 19th century--first, the experimental study of form, and
second, the criticism of the concepts or prejudices of evolutionary
morphology.
The period was characterised also by the great interest taken in
cytology, following upon the pioneer work of Hertwig, van Beneden and
others on the behaviour of the nuclei in fertilisation and
maturation.[519] This line of work gained added importance in connection
with contemporary research and speculation on the nature of hereditary
transmission, and it has in quite recent years received an additional
stimulus from the re-discovery of Mendelian inheritance. Its importance,
however, seems to lie rather in its possible relation to the problems of
heredity than in any meaning it may have for the problems of form. More
significant is the revolt against the cell-theory started by Sedgwick[520]
and Whitman,[521] on the ground that the organism is something more than
an aggregation of discrete, self-centred cells.
The experimental work on the causes of the production and restoration of
form infused new life into morphology. It opened men's eyes to the fact
that the developing organism is very much a living, active, responsive
thing, quite capable of relinquishing at need the beaten track of normal
development which its ancestors have followed for countless generations,
in order to meet emergencies with an immediate and purposive reaction.
It was cases of this kind, cases of active regulation in development and
regeneration, that led men like G. Wolff and H. Driesch to cast off the
bonds of dogmatic Darwinism and declare boldly for vitalism and
teleology.
There was the famous case of the regeneration of the lens in Amphibia
from the edge of the iris--an entirely novel mode of origin, not
occurring in ontogeny. The fact seems to have been discovered first by
Colucci in 1891, and independently by G. Wolff in 1895.[522] The
experiment was later repeated and confirmed by Fischel and other
workers. Wolff drew from this and other facts the conclusion that the
organism possesses a faculty of "primary purposiveness" which cannot
have arisen through natural selection.[523] And, as is well known, Driesch
derived one of his most powerful arguments in favour of vitalism from
the extraordinary regenerative processes shown by _Tubularia_ and
_Clavellina_ in the course of which the organism actually demolishes and
rebuilds a part or the whole of its structure. But under the influence
of physiologists like Loeb many workers held fast to materialistic
methods and conceptions.
The great variety of regulative response of which the organism showed
itself capable made it very difficult for the morphologist to uphold the
generalisations which he had drawn from the facts of normal undisturbed
development. The germ-layer theory was found inadequate to the new
facts, and many reverted to the older criterion of homology based on
destiny rather than origin. The trend of opinion was to reject the
ontogenetic criterion of homology, and to refuse any morphological or
phylogenetic value to the germ-layers.[524]
The biogenetic law came more and more into disfavour, as the developing
organism more and more showed itself to be capable of throwing off the
dead-weight of the past, and working out its own salvation upon original
and individual lines.[525] A. Giard in particular called attention to a
remarkable group of facts which went to show that embryos or larvae of
the same or closely allied species might develop in most dissimilar ways
according to the conditions in which they found themselves.[526] His
classical case of "poecilogeny" was that of the shrimp _Palaemonetes
varians_, the fresh-water form of which develops in an entirely
different way from the salt-water form.
Experimental workers indeed were inclined to rule the law out of
account, to disregard completely the historical element in development,
and this was perhaps the chief weakness of the neo-vitalist systems
which took their origin in this experimental work.
From the side also of descriptive morphology the biogenetic law
underwent a critical revision. It was studied as a fact of embryology
and without phylogenetic bias by men like Oppel, Keibel, Mehnert, O.
Hertwig and Vialleton,[527] and they arrived at a critical estimate of it
very similar to that of von Baer.
Theoretical objections to the biogenetic law had been raised from time
to time by many embryologists, but the positive testing of it by the
comparison of embryos in respect of the degree of development of their
different organs starts with Oppel's work of 1891.[528] He studied a large
number of embryos of different species at different stages of their
development, and determined the relative time of appearance of the
principal organs and their relative size. His results are summarised in
tabular form and have reference to all the more important organs. He was
led to ascribe a certain validity to the biogenetic law, but he drew
particular attention to the very considerable anomalies in the time of
appearance which are shown by many organs, anomalies which had been
classed by Haeckel under the name of heterochronies.
Oppel's main conclusions were as follows:--"There are found in the
developmental stages of different Vertebrates 'similar ontogenetic
series,' that is to say, Vertebrates show at definite stages
similarities with one another in the degree of development of the
different organs. Early stages resemble one another, so also do later
stages; equivalent stages of closely allied species resemble one
another, and older stages of lower animals resemble younger stages of
higher animals; young stages are more alike than old stages.... The
differences which these similar series show (for which reason they
cannot be regarded as identical) may be designated as temporal
disturbances in the degree of development of the separate organs or
organ-systems. Some organs show very considerable temporal dislocations,
others a moderate amount, others again an inconsiderable amount. Among
the developmental stages of various higher animals can be found some
which correspond to the ancestral forms and also to the lower types
which resemble these ancestral forms. On the basis of the tabulated data
here given there can be distinguished with certainty in the ontogeny of
Amniotes a pro-fish stage, a fish-stage, a land-animal stage, a
pro-amniote stage, and following on these a fully developed reptile,
bird or mammal stage."[529]
Oppel's methods were employed by Keibel[530] in his investigations on the
development of the pig, which formed the model for the well-known series
of _Normentafeln_ of the ontogeny of Vertebrates which were issued in
later years under Keibel's editorship. Keibel was more critical of the
biogenetic law than Oppel, and he held that the ancestral stages
distinguished by Oppel could not be satisfactorily established. He
suggested an interesting explanation of heterochrony in development,
according to which the premature or retarded appearance of organs in
ontogeny stands in close relation with the time of their entering upon
functional activity. Thus in many mammals the mesodermal part of the
allantois often appears long before the endodermal part, though this is
phylogenetically older. This Keibel ascribes to the fact that the
endodermal part is almost functionless. "One can directly affirm," he
writes, "that the time of appearance of an organ depends in an eminent
degree upon the time when it has to enter upon functional activity. This
moment is naturally dependent upon the external conditions. Among the
highest Vertebrates, the mammals, the traces of phylogeny shown in
ontogeny are to a great extent obliterated through the adaptation of
ontogeny to the external conditions, and through the modifications which
the germs of more highly organised animals necessarily exhibit from the
very beginning as compared with germs which do not reach such a high
level of development" (p. 754, 1897).
Study of individual variation in the time of appearance of the organs in
embryos of the same species was prosecuted with interesting results by
Bonnet,[531] Mehnert,[532] and Fischel.[533] Fischel found that variability
was greatest among the younger embryos, and became progressively less in
later stages. Like von Baer (_supra_, p. 114) he inferred that
regulatory processes were at work during development which brought
divergent organs back to the normal and enabled them to play their part
as correlated members of a functional whole.
Important theoretical views were developed by Mehnert[534] in a series of
publications appearing from 1891 to 1898. Like Keibel, Mehnert
emphasised the importance of function in determining the late or early
appearance of organs, but he conceived the influence of function to be
exerted not only in ontogeny, but also throughout the whole course of
phylogeny, by reason of the transmission to descendants of the effects
of functioning in the individual life.
In his paper of 1897 Mehnert details the results of an extensive
examination of the development of the extremities throughout the Amniote
series. He finds that in all cases a pentadactylate rudiment is formed,
even in those forms in which only a few of the elements of the hand or
foot come to full development. But whereas in forms with a normally
developed hand, _e.g._ the tortoise and man, all the digits develop and
differentiate at about the same rate, in forms which have in the adult
reduced digits, _e.g._ the ostrich and the pig, these vestigial digits
undergo a very slow and incomplete differentiation, while the others
develop rapidly and completely. He draws a general distinction between
organs that are phylogenetically progressive and such as are
phylogenetically regressive, and seeks to prove that progressive organs
show an ontogenetic acceleration and regressive organs a retardation.[535]
The acceleration or retardation affects not only the mass-growth of the
organs, but also their histological differentiation.
Now between progression and functioning and between regression and
functional atrophy there is obviously a close connection. Loss of
function is well known to be one of the chief causes of the degeneration
of organs in the individual life, and on the other hand, as Roux has
pointed out, all post-embryonic development is ruled and guided by
functioning. It is thus in the long run functioning that brings about
phylogenetic progression, absence of functional activity that causes
phylogenetic regression. This comes about through the transmission of
acquired functional characters, a transmission which Mehnert conceives
to be extraordinarily accurate and complete.
In general Mehnert adopts the functional standpoint of Cuvier, von Baer,
and Roux. His considered judgment as to the phylogenetic value of the
biogenetic law closely resembles that formed by von Baer, for he admits
recapitulation only as regards the single organs, not as regards the
organism as a whole. He has, however, much more sympathy with the law
than either Keibel or Oppel, though he agrees that it cannot be used for
the construction of ancestral trees. But he ascribes to it as a fact of
development considerable importance. The following passage gives a good
summary of his view as to the scope and validity of the law. "The
biogenetic law has not been shaken by the attacks of its opponents. The
assertion is still true that individual organogenesis is exclusively
dependent on phylogeny. But we must not expect to find that all the
stages in the development of the separate organs, which coexisted in any
member of the phylogenetic series, appear _at the same time_ in the
individual ontogeny of the descendants, because each organ possesses its
own specific rate of development. In this way it comes about naturally
that organs which become differentiated rapidly, as, for example, the
medullary tube, as a rule dominate earlier periods of ontogeny than do
the organs of locomotion. For the same reason the cerebral hemispheres
of man are almost as large in youth as in maturity. The picture which an
embryo gives is not a repetition in detail of one and the same
phylogenetic stage; it consists rather of an assemblage of organs, some
of which are at a phyletically early stage of development, while others
are at a phyletically older stage."[536]
A different line of attack was that adopted by O. Hertwig in a series of
papers, which contain also what is perhaps the best critical estimate of
the present position and value of descriptive morphology.[537]
It had not escaped the notice of many previous observers that quite
early embryos not infrequently show specific characters even before the
characters proper to their class, order and genus are developed--in
direct contradiction of the law of von Baer. Thus L. Agassiz[538] had
remarked in 1859 that specific characteristics were often developed
precociously. "The Snapping Turtle, for instance, exhibits its small
crosslike sternum, its long tail, its ferocious habits, even before it
leaves the egg, before it breathes through lungs, before its derm is
ossified to form a bony shield, etc.; nay, it snaps with its gaping jaws
at anything brought near, when it is still surrounded by its amnion and
allantois, and its yolk still exceeds in bulk its whole body" (p. 269).
Wilhelm His,[539] in the course of an acute and damaging criticism of the
biogenetic law as enunciated by Haeckel, showed clearly that by careful
examination the very earliest embryos of a whole series of Vertebrates
could be distinguished with certainty from one another. "An identity in
external form of different animal embryos, despite the common
affirmation to the contrary, does not exist. Even at early stages in
their development embryos possess the characters of their class and
order, nay, we can hardly doubt, of their species and sex, and even
their individual characteristics" (201).
This specificity of embryos was affirmed with even greater confidence by
Sedgwick in a paper critical of von Baer's law.[540] He wrote:--"If v.
Baer's law has any meaning at all, surely it must imply that animals so
closely allied as the fowl and duck would be indistinguishable in the
early stages of development; and that in two species so closely similar
that I was long in doubt whether they were distinct species, viz.,
_Peripatus capensis_ and _Balfouri_, it would be useless to look for
embryonic differences; yet I can distinguish a fowl and a duck embryo on
the second day by the inspection of a single transverse section through
the trunk, and it was the embryonic differences between the Peripatuses
which led me to establish without hesitation the two separate
species.... I need only say ... that a species is distinct and
distinguishable from its allies from the very earliest stages all
through the development, although these embryonic differences do not
necessarily implicate the same organs as do the adult differences" (p.
39).
Hertwig interprets this fact of the specific distinctness of closely
allied embryos in the light of the preformistic conception of heredity.
According to this view the whole adult organisation is represented in
the structure of the germ-plasm contained in the fertilised ovum, from
which it follows that the ova of two different species, and also their
embryos at every stage of development, must be as distinct from one
another as are the adults themselves, even though the differences may
not be so obvious. If this be the case there can be no real
recapitulation in ontogeny of the phylogeny of the race, for the
egg-cell represents not the first term in phylogeny, but the last. The
egg-cell _is_ the organism in an undeveloped state; it has a vastly more
complicated structure than was possessed by the primordial cell from
which its race has sprung, and it can in no way be considered the
equivalent of this ancestral cell.
Hertwig puts this vividly when he says that "the hen's egg is no more
the equivalent of the first link in the phylogenetic chain than is the
hen itself" (p. 160, 1906, b).
If ontogeny is not a recapitulation of phylogeny, how is it that the
early embryonic stages are so alike, even in animals of widely different
organisation? Hertwig's answer to this is very interesting. He takes the
view that many of the processes characterising early embryonic
development are the means necessarily adopted for attaining certain
ends. Such are the processes of segmentation, the formation of a
blastula, of cell-layers, of medullary folds where the nervous system is
a closed tube, the formation of the notochord as a necessary condition
of the development of the vertebral column, and so on. "Looked at from
this standpoint it cannot surprise us that in all animal phyla the
earliest embryonic processes take place in similar fashion, so that we
observe the occurrence both in Vertebrates and Invertebrates of a
segmentation-process, a morula-stage, a blastula and a gastrula. If now
these developmental processes do not depend on chance, but, on the
contrary, are rooted in the nature of the animal cell itself, we have no
reason for inferring from the recurrence of a similar
segmentation-process, morula, blastula, and gastrula in all classes of
the animal kingdom the common descent of all animals from one
blastula-like or gastrula-like ancestral form. We recognise rather in
the successive early stages of animal development only the manifestation
of special laws, by which the shaping of animal forms (as distinct from
plant forms) is brought about" (p. 178, 1906, b).
"The principal reason why certain stages recur in ontogeny with such
constancy and always in essentially the same manner is that they provide
under all circumstances the necessary pre-conditions through which alone
the later and higher stages of ontogeny can be realised. The unicellular
organism can by its very nature transform itself into a multicellular
organism only by the method of cell-division. Hence, in all Metazoa,
ontogeny must start with a segmentation-process, and a similar statement
could be made with regard to all the later stages" (p. 57, 1906, a).
Similarities in early development are therefore no evidence of common
descent, and in the same way the resemblances of adult animals, subsumed
under the concepts of homology and the unity of plan, are not
necessarily due to community of descent, but may also be brought about
by the similarity or identity of the laws which govern the evolution of
these animals. In the absence, therefore, of positive evidence as to the
actual lines of descent (to be obtained only from palaeontology),
homological resemblance cannot be taken as proof of blood relationship,
for homology is a wider concept than homogeny. The only valid definition
of homology is that adopted in pre-evolutionary days, when those organs
were considered homologous "which agree up to a certain point in
structure and composition, in position, arrangement, and relation to the
neighbouring organs, and accordingly possess identical functions and
uses in the organism" (p. 151, 1906, b).
The concept of homology has thus a value quite independent of any
evolutionary interpretation which may be superadded to it. "Homology is
a mental concept obtained by comparison, which under all circumstances
retains its validity, whether the homology finds its explanation in
common descent or in the common laws that rule organic development" (p.
151, 1906, b). As A. Braun long ago pointed out, "It is not descent
which decides in matters of morphology, but, on the contrary, morphology
which has to decide as to the possibility of descent."[541]
Hertwig, in a word, reverts to the pre-evolutionary conception of
homology. "We see in homology," he writes, "only the expression of
regularities (_Gesetzmaessigkeiten_) in the organisation of the animals
showing it, and we regard the question, how far this homology can be
explained by common descent and how far by other principles, as for the
present an open one, requiring for its solution investigations specially
directed towards its elucidation" (p. 179, 1906, b).
Holding, as he does, that no definite conclusions can be drawn from the
facts of comparative anatomy and embryology as to the probable lines of
descent of the animal kingdom, Hertwig accords very little value to
phylogenetic speculation. It is, he admits, quite probable that the
archetype of a class represents in a general sort of way the ancestral
form, but this does not, in his opinion, justify us in assuming that
such generalised types ever existed and gave origin to the present-day
forms. "It is not legitimate to picture to ourselves the ancestral forms
of the more highly organised animals in the guise of the lower animals
of the present day--and that is just what we do when we speak of
Proselachia, Proamphibia and Proreptilia" (p. 155, 1906, b).
He rejects on the same general grounds the evolutionary dogma of
monophyletic or almost monophyletic descent, and admits with Koelliker,
von Baer, Wigand, Naegeli and others that evolution may quite well have
started many times and from many different primordial cells.
There is indeed a great similarity between the views developed by O.
Hertwig and those held by the older critics of Darwinism--von Baer,
Koelliker, Wigand, E. von Hartmann and others. It is true the
philosophical standpoint is on the whole different, for while many of
that older generation were vitalists Hertwig belongs to the mechanistic
school.
But both Hertwig and the older school agree in pointing out the _petitio
principii_ involved in the assumption that the archetype represents the
ancestral form; both reject the simplicist conception of a monophyletic
evolution (which may be likened to the "one animal" idea of the
transcendentalists); both admit the possibility that evolution has taken
place along many separate and parallel lines, and explain the
correspondences shown by these separate lines by the similarity of the
intrinsic laws of evolution; finally, both emphasise the fact that we
know nothing of the actual course of evolution save the few indications
that are furnished by palaeontology, and both insist upon the unique
importance of the palaeontological evidence.[542]
It was a curious but very typical characteristic of evolutionary
morphology that its devotees paid very little attention to the positive
evidence accumulated by the palaeontologists,[543] but shut themselves up
in their tower of ivory and went on with their work of constructing
ideal genealogies. It was perhaps fortunate for their peace of mind that
they knew little of the advances made by palaeontology, for the evidence
acquired through the study of fossil remains was distinctly unfavourable
to the pretty schemes they evolved.
As Neumayr, Zittel, Deperet, Steinmann and others have pointed out, the
palaeontological record gives remarkably little support to the ideal
genealogies worked out by morphologists. There is, for instance, a
striking absence of transition forms between the great classificatory
groups. A few types are known which go a little way towards bridging
over the gaps--the famous _Archaeopteryx_, for example--but these do not
always represent the actual phylogenetic links. There is an almost
complete absence of the archetypal ancestral forms which are postulated
by evolutionary morphology. Amphibia do not demonstrably evolve from an
archetypal Proamphibian, nor do mammals derive from a single generalised
Promammalian type. Few of the hypothetical ancestral types imagined by
Haeckel have ever been found as fossils. The great classificatory groups
are almost as distinct in early fossiliferous strata as they are at the
present day. As Deperet says in his admirable book,[544] in the course of
a presentation of the matured views of the great Karl von Zittel, "We
cannot forget that there exist a vast number of organisms which are not
connected by any intermediate links, and that the relations between the
great divisions of the animal and vegetable kingdoms are much less close
than the theory [of evolution] demands. Even the Archaeopteryx, the
discovery of which made so much stir and appeared to establish a genetic
relation between classes so distinct as Birds and Reptiles, fills up the
gap only imperfectly, and does not indicate the point of bifurcation of
these two classes. Intermediate links are lacking between Amphibia and
Reptiles. Mammals, too, occupy an isolated position, and no zoologist
can deny that they are clearly demarcated from other Vertebrates;
indeed, no fossil mammal is certainly known which comes nearer to the
lower Vertebrates than does Ornithorhynchus at the present day" (p.
115).
To take a parallel from the Invertebrata, B. B. Woodward,[545] after
discussing the phylogeny of the Mollusca as worked out by the
morphologists and comparing it with the probable actual course of the
evolution of the group, as evidenced by fossil shells, sums up as
follows:--"The lacunae in our knowledge of the interrelationships of the
members of the various families and orders of Mollusca are slight
however, compared with the blank caused by the total absence from
palaeontological history of any hint of passage forms between the classes
themselves, or between the Mollusca and their nearest allies. Nor is
this hiatus confined to the Molluscan phylum; it is the same for all
branches of the animal kingdom. There is circumstantial evidence that
transitional forms must have existed, but of actual proof none whatever.
All the classes of Mollusca appear fully fledged, as it were. No form
has as yet been discovered of which it could be said that it in any way
approached the hypothecated prorhipidoglossate mollusc, still less one
linking all the classes" (p. 79).
Pointing in the same direction as the absence of transitional forms is
the undeniable fact that all the great groups of animals appear with all
their typical characters at a very early geological epoch. Thus, in the
Silurian age a very rich fauna has already developed, and
representatives are found of all the main Invertebrate groups--sponges,
corals, hydroid colonies, five types of Echinoderms, Bryozoa,
Brachiopods, Worms, many types of Mollusca and Arthropoda. Of
Vertebrates, at least two types of fish are present--Ganoids and
Elasmobranchs. In the very earliest fossiliferous rocks of all, the
Precambrian formation, there are remains of Molluscs, Trilobites and
Gigantostraca, similar to those which flourished in Cambrian and
Silurian times.
The contributions of palaeontology to the solution of the problems of
descent posed by morphology are, however, not all of this negative
character. The law of recapitulation is in some well-controlled cases
triumphantly vindicated by palaeontology. Thus Hyatt and others found
that in Ammonites the first formed coils of the shell often reproduce
the characters belonging to types known to be ancestral, and what is
more they have demonstrated the actual occurrence of the phenomenon
known as acceleration or tachygenesis, often postulated by speculative
morphologists.[546] This is the tendency universally shown by embryos to
reproduce the characters of their ancestors at earlier and earlier
stages in their development.
The most valuable contribution made by palaeontologists to morphology and
to the theory of evolution arose out of the careful and methodical study
of the actual succession of fossil forms as exemplified in limited but
richly represented groups. Classical examples were the researches of
Hilgendorf[547] on the evolution of _Planorbis multiformis_ in the
lacustrine deposits of Steinheim, those of Waagen[548] on the phylogeny of
_Ammonites subradiatus_, and the work of Neumayr and Paul[549] on
_Paludina_ (_Vivipara_).
These investigations demonstrated that it was possible to follow out
step by step in superjacent strata the actual evolution of fossil
species and to establish the actual "phyletic series."
To take an example from among the Vertebrates, Deperet has shown (_loc.
cit._, pp. 184-9), that the European Proboscidea, belonging to the three
different types of the Elephants, Mastodons and Dinotheria, have evolved
since the Oligocene epoch along five distinct but continuous lines. The
Dinotherian stock is represented at the beginning of the Miocene by the
relatively small form _D. cuvieri_; this changes progressively
throughout Miocene times into _D. laevius_, _D. giganteum_, and _D.
gigantissimum_. Among the Mastodons two quite distinct phyletic series
can be distinguished, the first commencing with _Palaeomastodon
beadnelli_ of the Oligocene, and evolving between the Miocene and
Pliocene into _Mastodon arvernensis_, after traversing the forms _M.
angustidens_ and _M. longirostris_, the second starting with the _M.
turicensis_ of the Lower Miocene and evolving through _M. borsoni_ into
the _M. americanus_ of the Quaternary. The phyletic series of the true
elephants in Europe are relatively short, and go back only to the
Quaternary, _Elephas antiquus_ giving origin to the Indian elephant, _E.
priscus_ to the African.
The careful study of phyletic series brought to light the significant
fact that these lines of filiation tend to run for long stretches of
time parallel to, and distinct from one another, without connecting
forms. This is clearly exemplified in the case of the Proboscidea, and
many other examples could be quoted. Almost all rich genera are
polyphyletic in the sense that their component species evolve along
separate and parallel lines of descent.[550] "Such great genera as the
genus _Hoplites_ among the Ammonites, the genus _Cerithium_ among the
Gastropoda, the genus _Pecten_ or the genus _Trigonia_ among the
Lamellibranchs, each comprise perhaps more than twenty independent
phyletic series" (Deperet, p. 200).
Variation along the phyletic lines is gradual[551] and determinate, and
appears to obey definite laws. The earliest members of a phyletic series
are usually small in size and undifferentiated in structure, while the
later members show a progressive increase in size and complexity. Rapid
extinction often supervenes soon after the line has reached the maximum
of its differentiation.
The general picture which palaeontology gives us of the evolution of the
animal kingdom is accordingly that of an immense number of phyletic
lines which evolve parallel to one another, and without coalescing,
throughout longer or shorter periods of geological times. "Each of these
lines culminates sooner or later in mutations of great size and highly
specialised characters, which become extinct and leave no descendants.
When one line disappears by extinction it hands the torch, so to speak,
to another line which has hitherto evolved more slowly, and this line in
its turn traverses the phases of maturity and old age which lead it
inevitably to its doom. The species and genera of the present day belong
to lines that have not reached the senile phase; but it may be surmised
that some of them, _e.g._ elephants, whales, and ostriches, are
approaching this final phase of their existence" (Deperet, p. 249).
It is one of the paradoxes of biological history that the
palaeontologists have always laid more stress upon the functional side of
living things than the morphologists, and have, as a consequence, shown
much more sympathy for the Lamarckian theory of evolution. The American
palaeontologists in particular--Cope, Hyatt, Ryder, Dall, Packard,
Osborn--have worked out a complete neo-Lamarckian theory based upon the
fossil record.
The functional point of view was well to the fore in the works of those
great palaeontologists, L. Ruetimeyer (1825-1895) and V. O. Kowalevsky
(1842-83), who seem to have carried on the splendid tradition of Cuvier.
Speaking of Kowalevsky's classical memoir, _Versuch einer natuerlichen
Classification der fossilen Hufthiere_, Osborn[552] writes:--"This work is
a model union of the detailed study of form and function with theory and
the working hypothesis. It regards the fossil not as a petrified
skeleton, but as having belonged to a moving and feeding animal; every
joint and facet has a meaning, each cusp a certain significance. Rising
to the philosophy of the matter, it brings the mechanical perfection and
adaptiveness of different types into relation with environment, with
changes of herbage, with the introduction of grass. In this survey of
competition it speculates upon the causes of the rise, spread, and
extinction of each animal group. In other words, the fossil quadrupeds
are treated _biologically_--so far as is possible in the obscurity of
the past" (p. 8). The same high praise might with justice be accorded to
the work of Cope on the functional evolution of the various types of
limb-skeleton in Vertebrates, and on the evolution of the teeth as well
as to the work of other American palaeontologists, including Osborn
himself.
Osborn's law of "adaptive radiation," which links on to Darwin's law of
divergence,[553] constitutes a brilliant vindication of the functional
point of view. "According to this law each isolated region, if large and
sufficiently varied in its topography, soil, climate, and vegetation,
will give rise to a diversified mammalian fauna. From primitive central
types branches will spring off in all directions, with teeth and
prehensile organs modified to take advantage of every possible
opportunity of securing food, and in adaptation of the body, limbs and
feet to habitats of every kind, as shown in the diagram [on p. 363]. The
larger the region and the more diverse the conditions, the greater the
variety of mammals which will result.
"The most primitive mammals were probably small insectivorous or
omnivorous forms, therefore with simple, short-crowned teeth, of
slow-moving, ambulatory, terrestrial, or arboreal habit, and with short
feet provided with claws. In seeking food and avoiding enemies in
different habitats the limbs and feet radiate in four diverse
directions; they either become _fossorial_ or adapted to digging habits,
_natatorial_ or adapted to _amphibious_ and finally to _aquatic_
habits, _cursorial_ or adapted to swift-moving, terrestrial progression,
_arboreal_ or adapted to tree life. Tree life leads, as its final stage,
into
LIMBS AND FEET.
Volant.
/
Fossorial. Arboreal.
\ /
Short-limbed, plantigrade, } Ambulatory
pentadactyl, unguiculate } or
Stem. } Terrestrial.
/ \
Natatorial. Cursorial
Amphibious. Digitigrade.
/ \
Aquatic Unguligrade.
TEETH.
Omnivorous.
{ Grass.
{ Fish. | { Herb.
Carnivorous { Flesh. | Herbivorous { Shrub.
\ { Carrion. | / { Fruit.
\ | / { Root.
\ | /
\ | / Myrmecophagous.
\ | / / Dentition reduced.
\ | / /
\ | / /
\ | / /
\ |/ /
Stem: Insectivorous.
the parachute types of the flying squirrels and phalangers, or into the
true flying types of the bats.... Similarly in the case of the teeth,
insectivorous and omnivorous types appear to be more central and ancient
than either the exclusively carnivorous or herbivorous types. Thus the
extremes of carnivorous adaptation, as in the case of the cats, of
omnivorous adaptation, as in the case of the bears, of herbivorous
adaptation, as in the case of the horses, or myrmecophagous adaptation,
as in the case of the anteaters, are all secondary" (_loc. cit._, pp.
23-4).
We have now reached the end of our historical survey of the problems of
form. What the future course of morphology will be no one can say. But
one may hazard the opinion that the present century will see a return to
a simpler and more humble attitude towards the great and unsolved
problems of animal form. Dogmatic materialism and dogmatic theories of
evolution have in the past tended to blind us to the complexity and
mysteriousness of vital phenomena. We need to look at living things with
new eyes and a truer sympathy. We shall then see them as active, living,
passionate beings like ourselves, and we shall seek in our morphology to
interpret as far as may be their form in terms of their activity.
This is what Aristotle tried to do, and a succession of master-minds
after him. We shall do well to get all the help from them we can.
[519] See E. B. Wilson's masterly book, _The Cell in
Development and Inheritance_, New York and London, 1900.
[520] _Q.J.M.S._, xxvi. 1886.
[521] _Wood's Holl Biological Lectures_ for 1893.
[522] _Arch. f. Ent.-Mech._, i., pp. 380-90, 1895.
[523] _Beitraege zur Kritik der Darwinschen Lehre_,
Leipzig, 1898.
[524] See E. B. Wilson, "The Embryological Criterion of
Homology," _Wood's Holl Biological Lectures_, Boston,
pp. 101-24, 1895; Braem, _Biol. Centrblt._, xv., 1895;
T. H. Morgan, _Arch. f. Ent.-Mech._, xviii.; J. W.
Jenkinson, _Mem. Manchester Lit. Phil. Soc._, 1906, and
_Vertebrate Embryology_, Oxford, 1913; A. Sedgwick,
article "Embryology" in _Ency. Brit._, p. 318, vol. xi.,
11th Ed. (1910).
[525] For a detailed treatment of this important point see
the remarkable volume of E. Schulz (Petrograd),
_Prinzipien der rationellen vergleichenden Embryologie_,
Leipzig, 1910.
[526] "La Poecilogonie," _Bull. Sci. France et Belgique_,
xxxix., pp. 153-87, 1905.
[527] _Un probleme de l'evolution. La loi biogenetique
fondamentale_, Paris and Montpellier, 1908.
[528] _Vergleichung des Entwickelungsgrades der Organe zu
verschiedenen Entwickelungszeiten bei Wirbeltieren_,
Jena, 1891.
[529] Quoted by Keibel, _Ergebn. Anat. Entwick._, vii., p.
741.
[530] "Studien zur Entwickelungsgeschichte des Schweines,"
Schwalbe's _Morphol. Arbeiten_, iii., 1893, and v.,
1895.
_Normentafeln zur Entwickelungsgeschichte des
Schweines_, Jena, 1897.
"Das biogenetische Grundgesetz und die Cenogenese,"
_Ergebn. Anat. Entw._, vii., pp. 722-92, 1897.
"U. d. Entwickelungsgrad der Organe," _Handb. vergl.
exper. Entwick. der Wirbelthiere_, iii., 3, pp. 131-48,
1906.
[531] "Beitraege zur Embryologie der Wiederkaeuer," _Arch.
Anat. Entw._, 1889.
[532] "Die individ. Variation d. Wirbeltierembryo,"
_Morph. Arbeit._, v., 1895.
[533] "U. Variabilitaet u. Wachstum d. embryonalen
Koerpers," _Morph. Jahrb._, xxiv., 1896.
[534] "Gastrulation u. Keimblaetterbildung der _Emys
lutaria taurica_," _Morph. Arbeit._, i., 1891.
"Kainogenese," _Morph. Arbeit._, vii., pp. 1-156, 1897,
and also separately. _Biomechanik, erschlossen aus dem
Prinzipe der Organogenese_, Jena, 1898.
[535] This law was foreshadowed by Reichert in 1837, when he
wrote:--"We notice in our investigation of embryos of different
animal forms that it is those organs, those systems, which in the
fully developed individual are peculiarly perfect, that in their
earliest rudiments and also throughout the whole course of their
development appear with the most striking distinctness" (Mueller's
_Archiv_, p. 135, 1837). See also his _Entwick. Kopf. nackt.
Amphib._, p. 198, 1838. So, too, Rathke notes how the elongated
shape of the snake appears even in very early embryonic stages
(_Entwick. Natter._, p. 111, 1839).
[536] Quoted by Keibel (p. 790, 1897) from the
_Biomechanik_.
[537] _Die Zelle und die Gewebe_, Jena, 1898, and the
subsequent editions of this text-book, published under
the title of _Allgemeine Biologie. Die Entwickelung der
Biologie im neunzehnten Jahrhundert_, Jena, 1900, 2nd
ed., 1908. "Ueber die Stellung der vergl.
Entwickelungslehre zur vergl. Anatomie, zur Systematik
und Descendenztheorie," _Handb. vergl. exper.
Entwickelungslehre der Wirbeltiere_, iii., 3, pp.
149-80, Jena, 1906. (1906, b). Also in Pt. I. of Vol. I.
(1906, a).
[538] _An Essay on Classification_, London, 1859.
[539] _Unsere Koerperform_, Leipzig, 1874.
[540] _Q.J.M.S._, xxxvi., pp. 35-52, 1894.
[541] Quoted by Hertwig. See also K. Goebel, "Die
Grundprobleme der heutigen Pflanzenmorphologie," _Biol.
Centrbl._, xxv., pp. 65-83, 1905.
[542] This is also emphasised by Fleischmann in his critical study of
evolutionary morphology entitled _Die Descendenztheorie_, Leipzig,
1901.
[543] The same remark applies to the bulk of speculation as to the
factors of evolution, with the exception of the contributions made
to evolution theory by the palaeontologists by profession, such as
Cope.
[544] _Les Transformations du Monde animal_, Paris, 1907.
[545] "Malacology _versus_ Palaeoconchology," _Proc.
Malacological Soc._, viii., pp. 66-83, 1908.
[546] Particularly by E. Perrier, "La Tachygenese," _Ann.
Sci. nat._ (_Zool._) (8), xvi., 1903.
[547] _Monatsber. k. Akad. Wiss._, Berlin, pp. 474-504,
1866.
[548] _Geognost. u. Palaeont. Beitraege_, ii., Heft 2, pp.
181-256, 1869.
[549] _Abhand. k.k. Geol. Reichsanstalt_, vii., Wien,
1875.
[550] The case for polyphyletism is very strongly put by
G. Steinmann in his book, _Die geologischen Grundlagen
der Abstammungslehre_, Leipzig, 1908.
[551] The steps in this chronological variation were
termed by Waagen "mutations."
[552] _The Age of Mammals in Europe, Asia, and North
America_, New York, 1910.
[553] _Origin of Species_, 6th ed., Chap. IV.
INDEX
ACTINOZOAN THEORY of Vertebrate Descent, 299-300
Adaptation as Conservative Principle--
Cuvier, 39, 76
Adaptation, Ecological--
Von Baer, 123
H. Milne-Edwards, 199
Lamarck, 221, 222, 223, 224, 227
Treviranus, 225 f.n.
C. Darwin, 231-2, 235, 239
Haeckel, 248, 263
Gegenbaur, 263
V. O. Kowalevsky, 362
Osborn, 362-4
Adaptation, Ecological, and Classification--
Bronn, 203
Adaptation of Parts. _See_ "Correlation, Functional," and "Conditions of
Existence"
Adaptive Radiation (Osborn), 362-4
Agassiz, A., 288 f.n., 295
On Coelom, 296
Agassiz, L.--
Criticism of Vertebral Theory of Skull, 157
Membrane and Cartilage Bones, 164
Transcendentalism, 203
Classification, 203 f.n.
Three-fold Parallelism, 230, 255
Influence on Darwin, 238
Specific Distinctness of Embryos, 353
Albertus Magnus, 17
Alcmaeon, 1
Aldrovandus, 18
Allman, 209
Analogy. _See also_ Homology.
Aristotle, 8-10
Owen, 108
Haeckel, 251
Gegenbaur, 266
Lankester, 267
Anaxagoras, 14
Anaximander, 14
Anaximenes, 1
Animal and Vegetative Lives--
Aristotle, 16, 32
Buffon, 26-7
Bergson, 26 f.n.
Cuvier, 26, 32
Bichat, 27-9
Oken, 94
K. G. Carus, 94
Von Baer, 116, 123, 131
Remak (Sensory and trophic layers), 210
Gegenbaur, 263
Annelid Theory of Vertebrate Descent, 274-85, 301
Archetype, Anatomical, 246, 302-3
E. Geoffroy, 54, 67
Owen, 104-7, 110
J. V. Carus, Huxley, 204
C. Darwin, 238 f.n.
Archetype, Anatomical, as Ancestral--
C. Darwin, 235, 247
Haeckel, 251
Gegenbaur, 265
Sedgwick, 300
Criticism of this idea--
O. Hertwig, 355-7
Archetype, Embryological, 168, 246, 302-3
Von Baer, 126, 132
Reichert, 139, 147, 149
Rathke, 151, 153
Huxley, 159-61
Archetype, Embryological, as Ancestral--
C. Darwin, 233, 236-7
Haeckel, 254, 289-91
Gegenbaur, 266
O. and R. Hertwig, 298
Sedgwick, 300
A. Kowalevsky, 300
Arendt, 162
Aristotle, 2-16, 17, 345, 364
_Historia Animalium_, 2
_De Partibus Animalium_, 2, 9
Knowledge of Animals, 3, 4
Comparative Embryology, 4
Classification of Animals, 4-6
Unity of Plan, 6-7, 10
Homology and Analogy, 7-10
Teleology and Correlation, 10-12
Law of Compensation, 11
Division of Labour, 12
Degrees of Composition--homogeneous and heterogeneous parts, 12-14, 169
Law of Development (Von Baer), 14
Scale of Beings, 14-16
Functional attitude, 15-16, 197
Animal and Vegetative Lives, 16, 32
Ascidian Theory of Vertebrate Descent, 269-73, 304
Atomists, 16
Atomists, "Biological," 192-4
Audouin, V.--
Unity of plan in Arthropods, 85-6
Law of Compensation, 86
Marine Zoology, 195
Autenrieth, 90, 96
Avicenna, 17
BABAK, E., 333
Baer, K. E. von, 113-32, 133, 251, 304, 345, 356
Founder of Embryology, 113
_Entwickelungsgeschichte der Thiere_, 114
Regulation of Development, 114, 350
Development as Differentiation, 115, 128
Germ-Layer Theory, 115-6, 118-119, 208-9, 296
Morphological Differentiation, 116-7
Histological Differentiation, 117-8
Tissues and Germ-Layers, 118
Double symmetrical Development, 118, 279
Criticism of Meckel-Serres Law, 120-3, 304
Theory of Types, 123-4, 289, 291
Law of Development, 124-6
Embryological Criterion, 126-8, 132, 138
Embryological Archetype, 126, 132
Types of Development, 127-8
Von Baer and Cuvier, 128-30
Functional attitude, 129
Relation to Transcendentalists, 129, 131
Criticism of Scale of Beings, 130
Vertebral Theory of Skull, 131, 142
Serial Homology, 131-2
Gill-slits, Gill-arches and Aortic arches, 135-6, 146
Membrane and Cartilage Bones, 162-3
Degrees of Composition, 172
Ova of Mammals, 175-6
Segmentation of Ovum, 186
Criticism of Evolution Theory, 229, 242
Influence on Darwin, 236, 238
Criticism of Darwinism, 242
Teleology and Correlation, 242
On Ascidians, 271
Baer's Law. _See_ "Development, Von Baer's Law"
Bagge, 187
_Balanoglossus_ Theory of Vertebrate Descent, 285-7
Balbiani, 330
Balfour, F. M., 247, 299
Annelid Theory, 282-4
Gastrulation and Gastraea Theory, 295
Mesoderm, 296 f.n.
Coelom, 297
Barfurth, D., 330
Barry, M., 186, 188
Bateson, W.--
Metamerism, Vegetative Repetition, 286
_Balanoglossus_ Theory, 286-7
On Phylogenetic Speculation, 302
Beard, J., 285
Belon, 18
Beneden van, and Julin, 271, 285, 346
Bensley, A. B., 311 f.n.
Bergmann, 187
Bergson, H., 26 f.n., 341, 345
Bernard, Claude, 195, 314
Bert, P., 315
Bichat, X., 27-30, 118, 132, 169, 178, 263
Animal and Vegetative Lives, 27-9
"General Anatomy," 29-30
_Vie propre_ of Tissues, 30
Biogenetic Law. _See_"Development, Haeckel's Law"
Bischoff, 138
Segmentation, 186, 188
Blainville, de, 96, 128, 141, 199 f.n.
Bojanus, 96, 97
Bonnet, C.--
Scale of Beings, 22-3, 220, 227
Evolution, 215
Regeneration, 315
Bonnet, R., 350
Bonnier, G., on Albertus Magnus, 17
Born, G., 330
Boveri, T., 270 f.n., 333
Braem, 347 f.n.
Braun, A., 355
Breschet, 138, 173
Bronn, H. G., 200-3, 248
_Naturphilosophie_, 201
Functional attitude, 201-3
Geometry of Organism, 201, 249
Theory of Types, 202
Principle of Connections, 202
Intrinsic Laws of Evolution, 202
Division of Labour, 202
Ecological Adaptation and Classification, 203
Brown, R., 171
Bruch, C., 203 f.n.
Buechner, 194, 248
Buffon, 24-7, 336
Scale of Beings, 24, 215
Unity of Plan, 24
Evolution, 24-5, 214
Classification, 25-6
Animal and Vegetative Lives, 26-7
Homology and Analogy, 27
Burckhardt, R., 3 f.n., 268 f.n.
Burdin, 96
Burmeister, 249 f.n.
Butler, S., 226 f.n., 313, 335-42
Relation to Lamarck, 335-7
Psychological Vitalism, 336-41
Heredity and Memory, 337-41
The Two Stages of Development, 337-9
Consciousness and Habit, 337-9
Recapitulation Theory, 339-40
Teleology, 341
CABANIS, 215
Camper, P., 45, 46
Carter, 293 f.n.
Carus, J. V.--
Criticism of Embryological Criterion, 167
Morphology and Physiology, 194
Vertebral Theory of Skull, 203
On Archetype, 204
Evolution, 230
Carus, K.G.--
Law of Parallelism, 94, 249
Vertebral Theory, 96
Geometry of Skeleton, 98-100
Splanchnoskeleton, 98, 140
Causal Morphology, 312-3, 315-34
Cell-Theory--
Schwann, 169, 173-86, 188
C. F. Wolff, 170
Schleiden, 170-2
Criticism of Schwann-Schleiden Theory, 185-8
Virchow, Leydig, 188
Cell-Theory and Germ-Layer Theory--
Remak, 209-12
Cell-Theory as Disintegrative--
Schwann, 180-5, 248
Vogt, 190-1
Virchow, 191
Haeckel, 248
Criticism of this idea--
Reichert, 192-3, 194
J. V. Carus, 194
Sedgwick, Whitman, 346
Cell-Theory, Influence on Morphology, 190
Cenogenesis, 258-9, 323
Chabry, 331
Child, C. M., 333
Chun, C, 317, 332
Classification of Animals--
Aristotle, 4-6
Rondeletius, Aldrovandus, Gesner, 18
Linnaeus, 22
Buffon, 25-6
Cuvier, 39-41
E. Geoffroy, 60
L. Agassiz, 203 f.n.
Lamarck, 216-7, 227, 228
Classification and Ecological Adaptation (Bronn), 203
Classification as Genealogical--
Buffon, 24-5
Lamarck, 218, 228
C. Darwin, 233, 234, 247
Haeckel, 250-1, 254
Criticism of this idea, 303, 304,
O. Hertwig, 356
Classification, Phylogenetic--
Haeckel's, 289-94
Claus, 259
Co-adaptation, 326 f.n.
Coelom--
Remak, 211
A. Kowalevsky, 270, 295, 297
Haeckel, 291, 295, 296
Lankester, 291, 297
Coelom, Theory of, 295-301
Cohen, 189
Coiter, 18
Colucci, 346
Compensation, Law of--
Aristotle, 11
Goethe, 49
E. Geoffroy, 72-3
Audouin, 86.
German Transcendentalists, 100
Condillac, 215
Conditions of Existence, Principle of--
Cuvier, 34, 75-6, 239
Gegenbaur, 263-4
Roux, 324, 326
Spencer, Weismann, 326 f.n.
Disregard for--
Lamarck, 226
C. Darwin, 232, 238-41
Haeckel, 248, 264
Conklin, 333
Connections, Principle of--
Goethe, 47
E. Geoffroy, 53-4, 62-3, 71, 74, 261
Audouin, 85
Connections, Principle of--_contd._
German Transcendentalists, 100
J. F. Meckel, 101
Owen, 107-8
Bronn, 202
C. Darwin, 234-5
Gegenbaur, 261
Semper, 279
In Embryology, 168
Main Principle of Morphology, 246, 302
Convergence--
Milne-Edwards, 199
I. Geoffroy St Hilaire, 199 f.n., 206
C. Darwin, 236
Friedmann, Willey, Vialleton, 306 f.n.
Convergence, Rejected by Evolutionary Morphologists, 305, 312
Hubrecht, 305-6
Cope, E. D., 342, 357 f.n., 361, 362
Correlation, Functional--
Aristotle, 10-12
Cuvier, 35-8, 239, 241
E. Geoffroy, 77
Von Hartmann, 240-1
Radl, 240 f.n., 241
Von Baer, 242
Gegenbaur, 264
Disregarded by--
C. Darwin, 235, 238-41
Haeckel, 248, 264
Coste, 134, 138, 176, 187
Crampton, 332
Cunningham, J. T., 284
Cuvier, 26, 31-44, 89, 196, 197, 199 f.n., 278, 345, 361
Functional attitude, 31-6, 65, 75-8, 200, 305
Animal and Vegetative Lives, 32
Degrees of Composition, 32-3
Teleology, 33-5
Functional Adaptedness, 33-5, 324
Principle of Conditions of Existence, 34, 75-6, 239
Correlation, 35-8, 239, 241
Metabolism, 38
Adaptation as Conservative Principle, 39, 76
Classification, 39-41
Principle of Subordination of Characters, 40
Criticism of Scale of Beings, 39-40, 130
Type Theory, 41, 124, 289, 291
Criticism of Evolution-Theory, 41-4, 129, 304
Variation, Limits of, 42
Palaeontological Succession, 43
Polemic with Geoffroy, 64-5, 74-8
Criticism of Vertebral Theory of Skull, 97-8
Influence on J. F. Meckel, 101
Criticism of Meckel-Serres Law, 129-30, 304
As Embryologist, 130
Criticism of Lamarck, 228
Cytology, 346
Cytoplasm of Egg, Organ-forming Stuffs, 332-3
DALL, 361
D'Alton, 113
Dareste, C., 315
Darwin, Charles, 78, 230-41, 271, 304, 307, 336, 362
Systematist and Field Naturalist, 230, 231
Palaeontological Succession, 231
Ecological Adaptation, 231-2, 235, 239
Species Problem, 231
Functional Adaptation, Disregard for, 232, 238-41
Classification as genealogical, 233, 234, 247
Unity of Plan due to Community of Descent, 233, 234-5, 239, 247
Embryological Archetype as ancestral, 233, 236-7
Rejects Meckel-Serres Law, 233, 236
Interpretation of Vestigial Organs, 233, 237
Organism as Historical Being, 233, 308
Rejects Scale of Beings, 234
Homology, 234-5, 247
Principle of Connections, 234-5
Anatomical Archetype as ancestral, 235, 247
Von Baer's Law interpreted phylogenetically, 236-7
Modifications inherited at corresponding age, 237
Monophyletism and Polyphyletism, 238
Causes of Success, 238, 241
Darwin, Erasmus, 214, 226 f.n., 229, 336
Darwin, Sir Francis, 344
Daubenton, 26
Degrees of Composition--
Aristotle, 12-14, 169
Glisson, 19
Malpighi, 20
Bichat, 29-30
Cuvier, 32-3,
Dujardin, 169, 188
Von Baer, 172
Effect of Invention of Microscope, 20
Relation to Cell-Theory, 169
Delage, 333
Delage and Herouard, 273 f.n.
Delpino, 345
Demaillet, 44
Democritus, 16
Deperet, C, 357
On Cuvier, 43
Absence of intermediary forms in Palaeontology, 358
Phyletic series and Polyphyletism, 360-1
Development, Von Baer's Law--
Aristotle, 14
Von Baer, 124-6
Prevost and Dumas, 125 f.n.
Reichert, 149-50, 351 f.n.
Milne-Edwards, 205-8
Lereboullet, 206-8
Criticised by--
Agassiz, 352-3
His, 353
Sedgwick, 353
O. Hertwig, 354
Phylogenetic Interpretation of--
Darwin, 236-7
Gegenbaur, 266
Relation to Haeckel's Law, 254, 256, 257
Development, Biogenetic Law (Haeckel)--
Haeckel, 251, 253-9, 291-4
F. Mueller, 252-3, 254, 257
Gegenbaur, 262
Roux, 319
Butler, 339-40
Orr, 342
Criticism of--
Vialleton, 348
Oppel, 348-9
Keibel, 349-50
Mehnert, 350-2
O. Hertwig, 352, 354-5
His, 353
Relation to Laws of Meckel-Serres and Von Baer, 254, 256, 257, 303, 309
Relation to Heredity and Development, 312-3
Influence of Causal Morphology, 347-8
Palaeontological Evidence for, 359
Development, Meckel-Serres Law--
Harvey, 18
Hunter, 22
E. Geoffroy, 69-70, 72
Serres, 80-3, 94, 203-4, 205-6
Kielmeyer, Autenrieth, Oken, 90
Development, Meckel-Serres Law-_contd._
Tiedemann, 91
J. F. Meckel, 91-3
K. G. Carus, 94
Criticism of--
Von Baer, 120-3, 304
Cuvier, 129-30, 304
Milne-Edwards, 205
Lereboullet, 206-8
C. Darwin, 233, 236
Analogy with Biogenetic Law, 254-7, 262, 303, 304, 309
Development, Meckel-Serres Law, Theory of Three-fold Parallelism--
L. Agassiz, 230, 255
Tiedemann, Vogt, 255 f.n.
Haeckel, 254-5
Development, The two periods of--
Roux, 320-4, 325, 327, 335
Butler, 337-9
Diogenes of Apollonia, 1
Disintegration. _See_ "Cell-Theory," and "Materialistic Attitude"
Division of Labour, Principle of--
Aristotle, 12
Milne-Edwards, 197-8
Bronn, 202
Gegenbaur, 264
Dohrn, A., 269, 274-8
Annelid Theory of Vertebrate Descent, 274-7, 303
Principle of Function-Change, 276-8, 307
Functional Attitude, 277-8, 307
Formal Attitude, 306
Doellinger, I., 113, 157
Dollo, 311
Donne, 173
D'Orbigny, 43
Driesch, H., 242, 331, 332, 333, 334, 345, 346-7
Duges, A., 86-8, 100, 134, 142, 146
Unity of Plan, 87
Polyzoic conception of Organism, 87-8
Membrane and Cartilage Bones, 163
Dujardin, 169, 188
Dumas. _See_ Prevost and Dumas
Dumeril, 96
Dumortier, 173
Dutrochet, 99 f.n., 130, 134
Duverney, 19
EAR-OSSICLES, Homology of--
E. Geoffroy, 56
Spix, 100
Rathke, 141, 150
Reichert, 144-7
_Echelle des etres. See_ "Scale of Beings."
Ehlers, 284
Eisig, H., 284, 285
Embryology, Comparative, Early Workers--
Aristotle, 4, 113
Fabricius, Harvey, 18, 113
Malpighi, 20, 113
Oken and Kieser, 90, 113
Haller, C. F. Wolff, J. F. Meckel, Tiedemann, 113
Embryology, Experimental, 317, 318, 330-3
Embryological Archetype. _See_ "Archetype, Embryological"
Embryological Criterion of Homology, 133-168, 347
Goethe, 49
E. Geoffroy, 72, 110
Cuvier, 75, 110, 130
Owen, 110-1
Von Baer, 126-8, 132, 138
Rathke, 138, 140-1
J. Mueller, 138
Reichert, 138-9, 144-7, 163
Vogt, 156-7
Huxley, 158-9, 166
Koelliker, 165-6
Criticised by--
Owen, J. V. Carus, 167
Empedocles, 1, 15
Engramm (Semon), 343
_Entwicklungsgesetz._ _See_ "Evolution, Intrinsic Laws of"
_Entwicklungsmechanik_, 315
Erasistratus, 17
Evolution Theory--
Lucretius, 16
Buffon, 24-5, 214
Cuvier's criticism, 41-4, 129, 304
E. Geoffroy, 66-9, 73, 228
J. F. Meckel, 92-3, 215, 228
Leibniz, 213
Kant, 213-4
Erasmus Darwin, 214, 229
C. Bonnet, Oken, Robinet, Treviranus, 215
Tiedemann, 215, 255 f.n.
Lamarck, 215-29
Von Baer, 229, 242
I. Geoffroy St Hilaire, J. V. Carus, 230
Charles Darwin, 230-41
Von Hartmann, 240-1, 244, 356
Koelliker, 243
Owen, 244
Milne-Edwards, 244-5
Haeckel, 250-9
Gegenbaur, 265
The Organism as an Historical Being, 308-13
C. Darwin, 233, 308
Haeckel, 252, 257
Sedgwick, 308
Roux, 313, 322-4
Butler, 313, 336-41
Evolution-Theory, Influence on Morphology, 302-13
Evolution, Intrinsic Laws of, 241
J. F. Meckel, 93
Bronn, 202
Von Baer, 229, 242, 356
Koelliker, Naegeei, 243, 356
Owen, 244
Von Hartmann, 244, 356
Milne-Edwards, 244-5
O. Hertwig, 354-5, 356-7
Wigand, 356
Deperet, 361
FABRICIUS, 18, 113
Fallopius, 18
Fischel, 346, 350
Fischer, 328
Fleischmann, 357 f.n.
Flourens, 46, 315
Fontana, 172
Forbes, E., 196
Formal Attitude, 246, 305
Goethe, 49
E. Geoffroy, 62-3, 71, 75-8, 305
Haeckel, 249, 257, 260
Gegenbaur, 261, 263
Semper, 279
Adopted by Evolutionary Morphologists, 302-8, 311-2, 314
Hubrecht, 305-6
Dohrn, 306
France, R., 345
Friedmann, 306 f.n.
Fuld, 333
Functional Adaptation, 316-7, 318, 320-9, 333, 344, 351
Functional Attitude--
Aristotle, 15-6, 197
Bichat, 27-9
Cuvier, 31-6, 65, 75-8, 200, 305
Goethe, 49-50
J. F. Meckel, 101
Owen, 109, 110, 111
Von Baer, 129
Milne-Edwards, 195, 197-200
J. Mueller, Reichert, 200
Bronn, 201-3
Lamarck, 222-6, 307, 335
Gegenbaur, 260, 263-4
Dohrn, 277-8, 307
Roux, 320-9, 335
Houssay, 333
Butler, 336-41
G. Wolff, 346
Driesch, 346-7
Giard, 347
E. Schulz, 347 f.n.
Keibel, 349-50
Mehnert, 350-1
American Palaeontologists, 361, 362
Ruetimeyer, 361
V. O. Kowalevsky, 361-2
Osborn, 362-4
Function-Change, Principle of--
Dohrn, 276-8, 306, 307
Eisig, 284
Fuerbringer, M., 282 f.n., 284, 323 f.n.
GALEN, 17
Gastraea Theory, 269, 288-95, 298, 299-3O1, 303
Gastrula, Discovery of, 288
Gaupp, E., 310 f.n.
Gegenbaur, C, 247, 260-7, 271, 285, 286, 288 f.n.
Division of Egg-nucleus, 188
Functional Attitude, 260, 263-4
Formal Attitude, 261, 263
Principle of Connections, 261
Embryology and Comparative Anatomy, 261-2, 263
Biogenetic and Meckel-Serres Laws, 262
Homology, 261, 263, 265, 266-7
Adaptation and Correlation, 263-4
Archetype as ancestral, 263 f.n, 265
On Phylogenetic Speculation, 265-6
Embryological Archetype, 266
Membrane and Cartilage Bones, 309, 310
Gemmill, J. F., 285 f.n., 312 f.n.
Geoffroy, Etienne, St Hilaire, 40, 52-78, 141
Unity of Plan, 52-65, 70 ff., as conservative, 75, 78
Principle of Connections, 53-4, 62-3, 71, 74, 261
Unity of Composition, 54, 70-1, 75-6, 200, 305
Archetype, 54, 67
Metastasis, 55-6, 59, 74
Opercular Bones, 56
Unity of Composition of Sternum, 57-60
Classification, 60
Vertebrates and Articulates, 60-4, 274, 278-9, 303
Formal Attitude, 62-3, 65, 71, 75-8, 305
Cephalopods and Vertebrates, 64-5
Scale of Beings, 64
Polemic with Cuvier, 64-5, 74-8
Evolution, 66-9, 73, 228
Biogenetic Law, 69
Teratology, 69, 315
Meckel-Serres Law, 70, 72
Criteria of Homology, 71, 72, 110
Law of Compensation, 72-3
Criticism of his Principles, 74
Relation to German Transcendentalists, 89, 100-1
Vertebral Theory of Skull, 96, 97
Influence on Darwin, 234-5, 238
Geoffroy, Isidore, St Hilaire, 65 f.n., 199 f.n., 230
Geometry of the Organism, 33
K. G. Carus, 98-100, 249
Bronn, 201, 249
Haeckel, J. Mueller, Burmeister, G. Jaeger, 249
Germinal Vesicle (Egg-nucleus), 175-7, 188, 291 f.n.
Germ-Layer Theory--
Von Baer, 115-6, 118-9, 208-9, 296
Pander, 119-20, 209
C. F. Wolff, 119-20
Rathke, 136, 208
Lereboullet, Bischoff, 208
Huxley, 208, 289
Remak, 209-12, 296
Germ-Layers and Gastraea Theory--
Haeckel, 289-95
Lankester, Balfour, 295
Germ-Layer Theory, Influence of Causal Morphology on, 347
Gesner, 18
Giard, A.--
On Ascidian Theory, 271-3
Adaptive Homology, 273
Poecilogeny, 347-8
Glisson, F., 19
Gluge, 173
Goebel, K., 356 f.n.
Goethe, 45-51, 65, 89, 250
Unity of Plan, 45-7, 51
Homology, 47
Principle of Connections, 47
Formal and Functional Attitudes, 48-50
Teleology, 48
Metamorphosis of Plants, 48
Repetition of parts, 48-9
Vertebral Theory of Skull, 49, 96, 97
Law of Compensation, 49
Embryological Criterion, 49
Organisms as Nature's Works of Art, 50
Goette, 259
Graaf, von, 175
Grew, N., 169
Gruber, 330
HAECKEL, Ernst, 247-60, 271, 314, 342, 353, 357
His sources, 248-50
Materialism, 248, 250
On Teleology, Heredity and Adaptation, 248, 263
Correlation, Disregard for, 248, 264
Geometry of the Organism (Promorphology), 249
Repetition of Parts (Tectology), 249-50
Classification as Genealogical, 250-1, 254
Archetype as ancestral, 251
Homology and Analogy, 251
Biogenetic Law, 251, 253-9, 291-4
Three-fold parallelism, 254-5
Scale of Beings, 255, 256-7
Organism as an Historical Being, 257
Prussianism, 257
Palingenesis, 258
Cenogenesis, 258-9
Heterotopy, Heterochrony, 259
Gastraea Theory, 269, 288-95
Phylogenetic Classification, 289-94
Criticism of Theory of Types, Monophyletism, 289, 291
Gastraea Theory and Biogenetic Law, 291-4
Primary stages of Ontogeny and Phylogeny, 291-3
Coelom, 291, 295, 296
Experimental Embryology, 317
Haller, 113
Harting, 284 f.n.
Hartmann, E. von--
On Darwin's conception of correlation, 240-1
Evolution, 244, 356
Hartog, M., 344
Harvey, 18, 113
Hatschek, 270 f.n., 299
Helmholtz, H. von, 195
Henle, 172
Hensen, V., 209 f.n.
Herbst, C., 333
Herder, 46
Heredity and Memory, 336-44
Hering, E., 341-2
"Heritage" Characters, 309, 322
Herlitzka, 332
Herophilus, 17
Hertwig, O., 163, 330, 331, 346
On C. F. Wolff, 119
Fertilisation, 291 f.n.
Membrane and Cartilage Bones, 309-10
Biogenetic Law, 352, 354-5
Von Baer's Law, 354
Intrinsic Laws of Evolution, 354-5, 356-7
Homology not necessarily Homogeny, 355-7
Unity of Plan not necessarily due to Community of Descent, 355-7
On Phylogenetic Speculation, 356
Hertwig, O. and R.--
Coelom Theory, 297-8
Nervous System of Coelentera, 299
Heterochrony, 259, 348, 349-52
Heterogeneous Generation (Koelliker), 243
Heterotopy, 259
Hilgendorf, 359
Hill, 311
Hippocratic Treatises, 2
His, W., 206 f.n., 209 f.n.
Causal Morphology, 316
Cytoplasm of Egg, Organ-forming Stuffs, 333
Specific Distinctness of Embryos, 353
Histological Differentiation (von Baer), 117-8
Histology. _See also_ "Cell-Theory"
Malpighi, 20
Stensen, 21
Bichat, 29-30, 169, 178
Von Baer, 117-8
Schwann, 178
Remak, 209-12
Hofer, B., 330
Hofmeister, 185
Homogeny, 267, 303, 355
Homology, 168, 303, 355-7. _See also_ "Connections, Principle of," and
"Embryological Criterion"
Aristotle, 7-10
Belon, 18
Buffon, 27
Goethe, 47
E. Geoffroy, 53, 71
Serres, 80
Owen, 107-9
Lamarck, 227
C. Darwin, 234-5, 247
Haeckel, 251
Gegenbaur, 261, 263, 265, 266-7
Giard, 273
Semper, 279
O. Hertwig, 355-7
Braun, 355
Homology, Genetic Definition of--
Gegenbaur, 266
Lankester, 267
O. Hertwig's criticism, 355-7
Homoplasy, 267
Hooke, R., 20, 169
Houssay, F., 19 f.n., 333
Hubrecht, A. A. W., 284, 295 f.n., 301, 305-6
Hunter, J., 22, 315
Huschke, 134-5, 136, 141, 146
Huxley, T. H., 157, 238, 247
On Rathke, 154 f.n.
Embryological Criterion, 158-9, 166
Embryological Archetype, 159-61
Criticism of Vertebral Theory of Skull, 161-2
Membrane and Cartilage Bones, 166-7
On Archetype, 204
Germ-Layer Theory, 208, 289
Criticism of Three-fold Parallelism, 230 f.n.
Coelom, 297
Ancestry of Marsupials, 311
Hyatt, A., 359, 361
INSTINCT and Morphogenesis, Analogy of, vi., 307, 312
Lamarck, 220, 226
JACOBSON , 164
Jaeger, G., 249 f.n.
_Jardin des Plantes_, Paris, 19
Jenkinson, J. W., 347 f.n.
On His, 316
Jones, Wharton, 138, 176
Julin, C., 271, 285
Jussieu, de, 40
KANT, I.--
Teleology, 35, 213, 242
Unity of Plan, 46, 213-4
Evolution, 213-4
Keibel, F., 348, 349-50
Kerkring, 131
Kielmeyer, 89, 90, 96
Kieser, 90
Kleinenberg, N., 277
Kohlbrugge, J., 44 f.n., 65 f.n.
Koelliker, A.--
On C. F. Wolff, 119
Vertebral Theory of Skull, 157
Membrane and Cartilage Bones, 164-6, 310
Embryological Criterion, 165-6
Cell-division, 187
Intrinsic Laws of Evolution, 243, 356
Saltatory Variation, 243
Kowalevsky, A., 269-71, 284, 285, 299, 300
Development of Amphioxus, 270
Ascidians, 270-1
Coelom, 270, 295, 297
Gastrula, 288
Kowalevsky, V. O., 361-2
Krause, 176
Kupffer, 271
LACAZE-DUTHIERS, H. de, 203 f.n., 315-6
On Ascidians, 271, 273
Lamarck, 44, 66, 78, 215-29
Relation to Buffon, 215
Scale of Beings, 215-8, 220-1, 227-8
As Evolutionary, 218, 220
Classification, 216-7, 227, 228
Species Problem, 216, 227
Materialism, 218-9, 222-3, 225-6
Psychological Vitalism, 219, 220-6, 307, 335
_Sentiment interieur_, 219-20, 222-3, 225
Ecological Adaptation, 221, 222, 223, 224, 227
Laws of Evolution, 221-5
Transmission of Acquired Characters, 221-2, 224
Subtle Fluids, 222
Use and Disuse, 223-4
Independence of Current Thought, 226-7
Homology and Analogy, 227
Reception of his Theory, 228-9
Lamarck and Butler, 335-7
Lang, A., 301
Lankester, Sir E. Ray, 247
Homology, Homogeny, Homoplasy, and Analogy, 267
_Balanoglossus_ Theory of Vertebrate Descent, 287
Germ-Layer Theory and Phylogenetic Classification, 291
Planula Theory, 295
On Coelom Theory, 296-7, 299 f.n.
Latreille, 86, 100
Laurencet, 64
Lavocat, 203 f.n.
Leeuenhoek, 20, 21, 169
Leibniz, 23, 213, 343
Lereboullet--
Von Baer's Law, 206-8
Germ-layer Theory, 208
Gastrula, 288 f.n.
Leucippus, 16
Leuckart, 193 f.n., 194, 297
Levy, O., 333
Leydig, 187, 188, 275 f.n., 285
Linnaeus, 22
Loeb, J., 333, 347
_Loi de Balancement_. _See_ "Compensation, Law of"
Loven, 186, 196
Lucretius, 16
On the Soul, 222 f.n.
Ludwig, 193, 194, 314
Lyell, Sir C., 228 f.n.
Lyonnet, 22
MACBRIDE, E. W., 287 f.n.
M'Kendrick, J.--
On Fontana, 172
Mackenzie, W., 345
Malpighi, M., 20-1, 113, 169
Marine Zoology, Rise of, 195-6
Materialistic Attitude, 246-7, 345, 364
Schwann, 180-5
Vogt, 190-1
Virchow, 191
Ludwig, 193
Materialistic Physiology, 193-4, 314-5, 347
Lamarck, 218-9, 222-3, 225-6
The Darwinians, 241, 308
Haeckel, 248, 250
Roux, 315, 317, 318-9, 329
Semon, 343
Rignano, 344
Loeb, 347
Criticism of this attitude--
Reichert, 192-3
Meckel, D. A., 95
Meckel, J. F., 113
Meckel-Serres Law, 91-3
Evolution, 92-3, 215, 228
Teratology, 93-4
Repetition of Parts, 95
Vertebral Theory of Skull, 96
Eclecticism, 101
Meckel's Cartilage, 141, 145
Meckel-Serres Law. _See_ "Development, Meckel-Serres Law"
Mehnert, E., 348, 350-2
Membrane and Cartilage Bones, 162-7, 309-10
Memory and Heredity, 336-44
Mendelism, 346
Mesenchyme, 298
Mesoderm, 209-11, 296, 297, 298
Metabolism--
Cuvier, 38
Schwann, 182-5
Roux, 324, 329
Metamerism, 94, 95, 100, 109, 131-2, 266-7, 274-5, 279, 282, 286, 299, 301
Metamorphosis of Plants, 48, 235
Metastasis, Principle of--
E. Geoffroy, 55-6, 59, 74
Owen, 106
Metschnikoff, E., 278 f.n., 285, 288
Criticism of Ascidian Theory, 271
Coelom, 295, 296, 297
Meyen, 170, 185
Meyer, E., 284
Meyranx, 64
Microscope, Invention of, 19
Milne-Edwards, H., 12, 86, 238
Marine Zoology, 195
Functional Attitude, 195, 197-200
Unity of Plan, 197
Division of Labour, 197-8
Ecological Adaptation, Convergence, 199
Von Baer's Law, Polemic with Serres, 204-8
Evolution, 244-5
Mirbel, 170, 171
Mivart, St G., 277
Mohl, von, 170, 185
Moldenhawer, 170
Moleschott, 194
Moquin-Tandon, A., 87
Morgan, T. H., 317 f.n., 332, 333, 347 f.n.
Mosaic Theory of Development, 330-3
Mueller, F., Biogenetic Law, 252-3, 254, 257
Mueller, H., 166
Mueller, J., 136, 209 f.n., 260, 285, 309, 345
Embryological Criterion, 138
Vertebral Theory of Skull, 142-4, 154, 157
On Reichert, 150
Cell Theory, 172-3
Division of Egg-nucleus, 188
Vitalism, 192
Marine Zoology, 196
Functional Attitude, 200
Mutations (Waagen), 361 f.n.
NAEGELI, 185, 243 f.n., 356
_Naturphilosophie._ _See_ "Philosophy of Nature"
Nesbitt, R., 162
Neumayr, 357, 360
Nussbaum, M., 330
OKEN, L., 89, 113, 131, 134, 149
Meckel-Serres Law, 90-1
Teratology, 91
Repetition of Parts, 94-5
Serial Homology, 95-6, 100
Vertebral Theory, 96, 97, 98
On Geoffroy, 100
Influence on Serres, 205
Evolution, 215
Ollier, 315
Oppel, A., 318 f.n., 324 f.n., 327, 348-9
Orr, H. F., 342
Osborn, H. F., 214 f.n., 361
On V. O. Kowalevsky, 362
Functional Attitude, 362-4
Law of Adaptive Radiation, 362-4
Owen, R., 97, 102-12, 204
Eclecticism, 102
Vertebral Theory of Skeleton, 103-7
Archetype of Vertebrate Skeleton, 104-7, 110
Vertebral Theory of Skull, 104-6
Metastasis, 106
Principle of Connections, 107-8
Anatomy and Embryology, 108
Homology and Analogy, 108
Classes of Homology, 108-9, 266
Functional Attitude, 109, 110, 111
Embryological Criterion, 110, 167
Homological and Teleological Compoundedness, 110-1
Vegetative Repetition of Parts, 111, 286
Unity of Plan as Conservative Principle, 112
Influence on Darwin, 234, 235, 238
Evolution, 244
PACKARD, 361
Palaeontological Record, 357-61
Absence of connecting forms, 357-9
Biogenetic Law, 359
Phyletic Series, 359-61
Palaeontological Succession--
Cuvier, 43
E. Geoffroy, 67
L. Agassiz, 230, 255
C. Darwin, 231
Milne-Edwards, 245
Tiedemann, 255 f.n.
Paley, W., 341
Palingenesis (Haeckel), 258, 323
Pander, 113, 119-20, 133, 208, 209
Parallelism, Theory of. _See_ "Development, Meckel-Serres Law"
Three-fold. _See_ "Development, Meckel-Serres Law"
Paris Museum of Natural History, 19, 89, 101
Paul, 360
Pauly, A., 345
Perrault, C., 19
Perrier, E., 88, 359 f.n.
Pflueger, E., 317, 330
Philipeaux, 315
"Philosophy of Nature," 89, 94, 98, 203, 248
Phyletic Series, 359-61
Physiology, Separation from Morphology, 194, 247, 260, 314
Physiology of Development, 315
Planula Theory (Lankester), 295
Plato, 15
Pockels, 138
Poecilogeny (Giard), 347-8
Poli, 175
Polyphyletism--
Darwin, 238
Von Baer, 242, 356
Koelliker, Wigand, Naegeli, 356
Deperet, 360-1
Steinmann, 360 f.n.
Polyzoic Conception of Organism--
Duges, 87
Perrier, 88
Prevost and Dumas, 125 f.n., 134, 175, 186
Promorphology (Haeckel), 249
Protoplasm, 169, 188-9
Purkinje, 172, 173, 175, 176, 189
QUATREFAGES, A. de, 172, 195-6
RADL, E., on Goethe, 48
Correlation, 240 f.n., 241
On Darwin's Critics, 242 f.n.
On Cuvier's Critics, 278 f.n.
Rathke, H., 133, 136-7, 174, 194, 269, 351 f.n.
Discovery of Gill-slits in Pig and Chick, 134
Discovery of Gill-slits in Man, 135
Germ-Layer Theory, 136, 208
Embryological Criterion, 138, 140-1
Homologies of Gill-arches, 139-41, 146, 150
Development of Skull, 141, 150-4
Vertebral Theory of Skull, 141, 154-6
Embryological Archetype, 151, 153
Membrane and Cartilage Bones, 163, 166
Rauber, A., 330
Reaumur, 22, 315
Recapitulation Theory. _See_ "Development, Biogenetic Law"
Regeneration, 315, 318, 333, 346
Regulatory Processes in Development, 114, 319, 333, 346-7, 350
Reichert, C. B., Embryological Criterion, 138-9, 144-7, 163
Archetype, 139, 147, 149
Homologies of Gill-arches and Ear-ossicles, 144-7
Vertebral Theory of Skull, 147-9, 157
Von Baer's Law, 149-50, 351 f.n.
Membrane and Cartilage Bones, 163, 165, 166, 310
Criticism of "Biological Atomists," 192-3, 194
Functional Attitude, 193, 200
Remak, R., 118, 288 f.n.
On Vertebrae, 157
Cell Theory, 173, 187-8, 209
Microscopical Technique, 209 f.n.
Germ-Layer Theory, 209-12, 296
Cells, Tissues and Germ-Layers, 209-12
Mesoderm, 209-11
Coelom, 211, 296
Repetition of Parts within the Organism, Theory of. _See also_
"Vertebral Theory of Skull"
Goethe, 48-9
Duges, 87-8
Oken, 94-5
J. F. Meckel, D. A. Meckel, 95
Haeckel (Tectology), 249-50
Reymond, E. du Bois, 194, 314
Rignano, E., 343-4
Robinet, 23, 215
Rondeletius, 18
Rosenhof, Roesel von, 22
Roux, W., 313, 315-29, 344, 351
_Entwicklungsmechanik_, 315, 317-8
Materialistic Attitude, 315, 317, 318-9, 329
Functional Adaptation, 316-7, 318, 320-9, 333
Experimental Embryology, 317, 318, 330-1
Simple and Complex Components, 318-20
Functional Definition of Life, 320
Functional Attitude, 320-9, 335
The Two Periods of Development, 320-4, 325, 327, 335
Mosaic Theory of Development, 323, 330-1
Metabolism, 324, 329
Structure, Functional and Non-functional, 324-6
Functional Unity of Organism, 326
Functional Adaptation of Blood-vessels, 326-9
Form as manifestation of Activity, 329
Ruini, C., 18
Rusconi, 133-4, 186
Ruetimeyer, L., 361
Ryder, 361
SACHS, J. von, 170
St Ange, M., 146
Salensky, 259
Saltatory Variation--
E. Geoffroy, 78
Von Baer, 242
Koelliker, 243
Owen, 244
Sarcode, 169
Sars, M., 186, 196
Savigny, J. C., 83-5, 100, 137, 271
Scale of Beings, 89, 206, 214-5
Aristotle, 14-6
Anaximander, Anaxagoras, 14
Empedocles, Plato, 15
Albertus Magnus, 17
C. Bonnet, 22-3
Robinet, 23
Buffon, 24
E. Geoffroy, 64
Lamarck, 215-8, 220-1, 227-8
As Evolutionary, 218, 220
Haeckel, 256-7
Criticism of this idea--
Cuvier, 39-40, 130
Von Baer, 130
Milne-Edwards, 205
Lereboullet, 207
Darwin, 234
Haeckel, 255
Relation to Evolution-Theory, 214-5
Schepelmann, 333
Schleiden, 170-2
Schmieden, 328
Schults, C. H., 173
Schultze, Max, 189
Schultze, O., 331
Schulz, E., 347 f.n.
Schwann, Theodor, 169, 173-86, 248
Physiological Standpoint, 173, 179, 180, 182
Development of Cells, 174-5, 179-80
Cellular Nature of Ovum, 175-7
Development of Tissues from Cells, 177-8
Histology, 178
Materialism and Teleology, 180-3, 185
Cell-metabolism, 182-5
Cells as organic Crystals, 184-5
Sedgwick, A., 347 f.n.
Actinozoan Theory of Vertebrate Descent, 299-300
Metamerism, 299
Embryological Archetype, 300
Organism as Historical Being, 308
Cell-Theory, 346
Von Baer's Law, 353
Segmentation of Ovum, 186-8
Seiler, 138
Selection, Natural and Artificial, 307 f.n.
Self-Differentiation (Roux), 319, 320-1, 322, 323, 324, 327
Self-Regulation (Roux), 319
Semon, R., 342-3
Semper, C., 259, 269, 278-82, 284, 286
Annelid Theory, 274, 278-82
Metamerism, 274, 279, 282
Follower of Geoffroy, 278
Unity of Plan and Composition, 279, 303
Principle of Connections, 279
Formal Attitude, 279
_Sentiment interieur_ (Lamarck), 219-20, 222-3, 225
Serial Homology. _See_ "Metamerism"
Serres, E., 79-83, 91, 100, 205-6, 257 f.n.
Criteria of Homology, 80
Law of parallelism, 80-3, 94, 203-4, 205-6
Law of Multiple Formation, 80-1
Unity of Plan, 83, 205, 206
Teratology, 83
Meckel's Cartilage, 145 f.n.
Transcendentalism, 205-6
Concrescence Theory, 206 f.n.
Severino, 18
Sharpey, 162, 176
Siebold, von, 186
Skull, Development of, 139-62.
_See also_ "Vertebral Theory"
Spallanzani, 315
Species-Problem--
Cuvier, 42
Lamarck, 216, 227
Darwin, 231
Spencer, H., 326 f.n.
Spengel, 285, 287
Spinoza, 343
Spix, 96, 97, 100, 141
Stannius, 165
Steenstrup, 309
Steinmann, G., 357, 360 f.n.
Stensen (Steno), 21
Swammerdam, 20, 21-2
TACHYGENESIS, 359
Technique, Microscopical, 209 f.n., 268
Tectology (Haeckel), 249
Teleology--
Aristotle, 10
Cuvier, 33-5
Kant, 35, 213, 242
Von Baer, 242
Owen, Von Hartmann, 244
Butler, 341
G. Wolff, Driesch, 346
Criticism of--
Goethe, 48
Schwann, 180-2
The Darwinians, 241
Haeckel, 248
Evolutionary Morphologists, 308
Teratology, 69, 83, 91, 93, 315
Thienemann, 23 f.n.
Thompson, D'Arcy W., 2 f.n.
Thomson, A., 176
Thomson, J. Arthur, 215 f.n.
Tiedemann, 91, 113, 215, 255 f.n.
Tissues and Germ-Layers, 118, 209-12
Transcendental Anatomy, Relation to Evolutionary Morphology, 302-8, 312
Transcendentalism, French and German Schools, 89, 100
Trembley, 22, 315
Treviranus, 141, 170, 215, 225 f.n.
Turpin, 173
Types, Theory of (Cuvier and Von Baer)--
Cuvier, 41, 124, 289, 291
Von Baer, 123-4, 289, 291
Bronn, 202
Lereboullet, 207
Types, Theory of (Cuvier and Von Baer)--_contd._
Criticised by--
E. Geoffroy, 60
Haeckel, 289, 291
Lankester, 291
Type-Theory and Evolution, 304
UNGER, 185
Unity of Composition, Principle of, Geoffroy, 54, 70-2, 75-6, 200, 305
Unity of Plan, 88, 241, 278-9, 303, 312. _See also_ "Archetype"
Aristotle, 6-7, 10
Belon, Severino, 18
Perrault, 19
Robinet, 23
Buffon, 24
Cuvier, 41
Goethe, 45-7, 51
Vicq D'Azyr, 45
Camper, 45, 46
Herder, 46
Kant, 46, 213-4
E. Geoffroy, 52-65, 70 ff.
Serres, 83, 205, 206
Savigny, 83
Audouin, 85-6
Latreille, 86
Duges, 86-7
J. F. Meckel, 101
Milne-Edwards, 197
Semper, 279
Haeckel, 289, 291
Lankester, 291
Unity of Plan as due to Community of Descent--
Darwin, 233, 234-5, 239, 247
Haeckel, 250-1
Gegenbaur, 263 f.n., 265
Criticism of this idea--
O. Hertwig, 355-7
Unity of Plan as Conservative Principle--
E. Geoffroy, 75, 78
Owen, 112
Gegenbaur, 263-4
Evolutionary Morphologists, 307
VALENTIN, 138, 173, 176
Variation, Limits of, Cuvier, 42
Vegetative Repetition of Parts--
Owen, 111, 286
Bateson, 286
Velpeau, 138
Vertebral Theory of Skull, 49, 96-9, 104-6, 131, 141-4, 147-9, 154-7,
161-2, 165, 203, 235, 310 f.n.
Vertebrate Descent, 269-87, 299-301, 304
Verworn, M., 330
Vesalius, 18
Vestigial Organs, 233, 237, 309, 312
Vialleton, L., 306 f.n., 348
Vicq d'Azyr, 45, 95
Virchow, R., 188, 191
Vitalism, Psychological--
Lamarck, 219, 220-6, 307, 335
Butler, 336-41
Orr, Cope, 342
Ward, 343
Delpino, France, Pauly, A. Wagner, Mackenzie, 345
Vogt, C.--
Criticism of Vertebral Theory, 156-7
Capillaries, 179
Segmentation, 186
Materialistic Attitude, 190-1
Threefold Parallelism, 255 f.n.
WAAGEN, 359, 361 f.n.
Wagner, A., 345
Wagner, R., 176
Ward, J., 343
Weber, 138
Weismann, A., 240, 323, 326 f.n., 330-1, 343
Werneck, 173
Whitman, C. O., 346
Wigand, A., 242 f.n., 356
Willey, A., 273 f.n., 306 f.n.
Williamson, 309
Willis, 19
Wilson, E. B., 331, 332-3, 346 f.n., 347 f.n.
Wolff, C. F., 113
Germ-layer Theory, 119-20
Cells, 170
Wolff, G., 346-7
Woodward, B. B., 358
Wotton, E., 17
ZELENY, 333
Zittel, K. von, 357, 358
Zoja, 331
* * * * *
PRINTED BY
OLIVER AND BOYD,
EDINBURGH, SCOTLAND
* * * * *
HEREDITY. By J. Arthur Thompson, M.A., LL.D., Regius Professor
of Natural History in the University of Aberdeen. With numerous
Illustrations. 9s. _net_.
CONTENTS
Heredity and Inheritance: Defined and Illustrated--The Physical Basis
of Inheritance--Heredity and Variation--Common Modes of
Inheritance--Reversion and allied Phenomena--Telegony and other
Dispute Questions--The Transmission of Acquired Characters--Heredity
and Disease--Statistical Study of Inheritance--Experimental Study of
Inheritance--History of Theories of Heredity and Inheritance--Heredity
and Development--Heredity and Sex--Social Aspects of Biological
Results--Bibliography--Subject-Index to Bibliography--Index.
"We all know books of science which we ought to read with pleasure,
but to which we turn with shrinking. Full, perhaps, of new facts and
ideas, they are so expressed as to bore consumedly. 'Heredity' belongs
to another category. He who runs may read, even if he be a beginner,
and he who reads will probably not cease to run until he has traversed
the last page."--_Nature_.
"This is certainly the best modern book on heredity to recommend to
the student and the intelligently curious."--_Science Progress_.
"May be regarded as the standard work of reference on this subject. As
a judicial summary of an exceedingly difficult and controversial
subject it is masterly, while in the matter of clearness of exposition
it has no rival."--_Knowledge_.
RECENT ADVANCES IN THE STUDY OF VARIATION, HEREDITY AND EVOLUTION.
By Robert H. Lock, M.A., sometime Fellow of Gonville and Caius
College, Cambridge, late Assistant-Director of the Royal Botanic
Gardens, Ceylon. With Portraits and other Illustrations. Revised by L.
Doncaster, D.Sc., F.R.S. With a Biographical Note by Bella Sidnay
Woolf (Mrs R. H. Lock). Crown 8vo.
MICROSCOPY. The Construction, Theory, and Use of the Microscope. By
Edmund J. Spitta, F.R.A.S., F.R.M.S., etc. With numerous Diagrams and
Illustrations. Second Edition. 12s. 6d. _net_.
"Let us hasten to urge every student of the microscope who wishes to
gain a thorough understanding of its principles and possibilities and
its defects, and every user of the instrument who desires a work of
reference to which he may turn for an explanation of some unexplained
optical phenomenon, or for particulars of up-to-date apparatus, to
procure a copy of Mr Spitta's book without delay."--_Nature_.
CONVERGENCE IN EVOLUTION. By Arthur Willey, D.Sc. (Lond.); Hon. M.A.
(Cantab.); F.R.S. With Diagrams. Demy 8vo. 7s. 6d. _net_.
This work brings together some scattered facts of parallel development
of outward form and internal structure in the Animal kingdom,
introducing new cases and fresh interpretations. It is, taken as a
whole, an original contribution to the theory of organic evolution,
with special reference to the forms of Animal life.
THE HEREDITY OF ACQUIRED CHARACTERS IN PLANTS. An aspect of the true
Darwinism based on Personal Observations and Experiments. By the Rev.
Prof. George Henslow. With Illustrations. Demy 8vo. 6s. _net_.
A HANDBOOK OF PHYSIOLOGY. By W.D. Halliburton, M.D., F.R.S., Professor
of Physiology, King's College, London. Eleventh Edition, being the
Twenty-fourth of Kirkes'. With nearly Seven Hundred Illustrations,
including some Coloured Plates. Large Crown 8vo. 15s. _net_.
"One of the best manuals for the student which we possess ... the book
is an eminently trustworthy one, and will prove a valuable foundation
for, and introduction to, the large treatises on
physiology."--_Lancet_.
THE BACTERIOLOGY OF MILK. By Harold Swithinbank, of the
Bacteriological Research Laboratory, Durham, and Sir George Newman,
M.D., F.R.S.E., D.P.H., Chief Medical Officer, Board of Education.
With Special Chapters also by Dr Newman on Spread of Disease by Milk
and the Control of the Milk Supply. With numerous Illustrations. Royal
8vo. 25s. _net_.
"Ought to find a place in the library of every medical officer of
health and of every milk-producer. Scientific in method and lucid in
exposition, the authors have given us a really invaluable
text-book."--_Spectator_.
BACTERIOLOGY AND THE PUBLIC HEALTH. By Sir George Newman, M.D., F.R.S.
(Edin.), D.P.H., Chief Medical Officer, Board of Education. With
Illustrations. Medium 8vo. 21s. _net_.
"The present work, though nominally a third edition of 'Bacteria in
Relation to the Economy of Nature, Industrial Processes, and the
Public Health,' is virtually a new book, written with the object of
supplying all that is necessary for the student of hygiene and the
officer of health to know, so far as every-day problems of sanitation
and preventive medicine demand.... Dr Newman has done a good work in
producing a treatise which places at the service of the community what
is known about all these topics."--_Daily Telegraph_.
THE RECENT DEVELOPMENT OF PHYSICAL SCIENCE. By W.C.D. Whetham, M.A.,
F.R.S. Illustrated. Large Crown 8vo. 5s. _net_.
The Philosophical Basis of Physical Science--The Liquefaction of Gases
and the Absolute Zero of Temperature--Fusion and Solidification--The
Problems of Solution--The Conduction of Electricity Through
Gases--Radio-Activity--Atoms and AEther--Astro-Physics--Index.
THE REALM OF NATURE. An Outline of Physiography. By H.R. Mill, D.SC,
LL.D., Director of the British Rainfall Organisation. Second Edition.
Revised and entirely reset. With 19 coloured Maps and 73 Illustrations
in the text. Crown 8vo. 5s. _net_.
"Dr Mill is to be congratulated on having now brought his information,
so far as space permitted, well up to date. The most striking features
of the work are its comprehensiveness and conciseness.... It would,
indeed, be difficult to point to any other English work on
physiography giving so much trustworthy matter in equally condensed
form, yet so readable."--_Athenaeum_.
NATURE AND ORIGIN OF FIORDS. By J.W. Gregory, D.Sc., F.R.S., Author of
"The Dead Heart of Australia." With Illustrations. Demy 8vo. 16s.
_net_.
Professor T.G. Bonney says in _Nature_, 12th Feb. 1914:--"But we must
conclude, and do this by expressing our hearty thanks to him for this
admirable history of fiords and other forms of inlets of the sea. It
will be a great boon to students, for it is a veritable encyclopaedia,
full of important facts."
MECHANISM, LIFE AND PERSONALITY. An Examination of the Mechanistic
Theory of Life and Mind. By J.S. Haldane, M.D., LL.D., F.R.S., Fellow
of New College and Reader in Physiology, University of Oxford. Crown
8vo. 2s. 6d. _net_.
"Dr Haldane has succeeded in packing an immense amount of knowledge
and thought into the compass of a small volume. The complexity of his
themes has never for a moment betrayed him into ambiguity either of
thought or expression, and the pervading temptation to stray into
bypaths, the failure to resist which makes the weakness of so much
otherwise fine work of this class, has been most successfully
resisted. The clarity of the book may fairly be described as
remarkable."--_Sunday Times_.
* * * * *
THE PROGRESSIVE SCIENCE SERIES
THE INTERPRETATION OF RADIUM. By Frederick Soddy, M.A., Independent
Lecturer in Physical Chemistry and Radio-activity in the University of
Glasgow. With Illustrations. _6s. net_.
HEREDITY. By J. Arthur Thomson, M.A, Regius Professor of Natural
History in the University of Aberdeen. Illustrated. _9s. net_.
THE PROBLEM OF AGE, GROWTH, & DEATH. A Study of Cytomorphosis. By
Charles S. Minot, LL.D. (Yale, Toronto), D.Sc. (Oxford). Illustrated.
_6s. net_.
THE SOLAR SYSTEM. A Study of Recent Observations. By Charles Lane
Poor, Professor of Astronomy in Columbia University. Illustrated. _6s.
net_.
PROBLEMS OF LIFE AND REPRODUCTION. By Marcus Hartog, M.A., D.Sc,
Professor of Biology in the University, Cork. Illustrated. _7s. 6d.
net_.
CLIMATE. Considered Especially in Relation to Man. By Robert de Courcy
Ward, Assistant Professor of Climatology in Harvard University.
Illustrated. _6s. net_.
HYGIENE OF NERVES AND MIND IN HEALTH AND DISEASE. By August Forel,
M.D. Translated from the German by A. Atkins. Illustrated. _6s. net_.
INFECTION AND IMMUNITY. By George S. Sternberg, M.D., LL.D. _6s. net_.
THE STARS. A Study of the Universe. By Professor Simon Newcomb.
Illustrated. _6s. net_.
A BOOK OF WHALES. By F.E. Beddard, M.A., F.R.S. (The Editor).
Illustrated. _6s. net_.
THE STUDY OF MAN: An Introduction to Ethnology. By Professor A.C.
Haddon, D.SC, M.A., M.R.I.A. Illustrated. _6s. net_.
THE GROUNDWORK OF SCIENCE. A Study of Epistemology. By St. George
Mivart, M.D., PH.D., F.R.S. _6s. net_.
EARTH SCULPTURE; or, The Origin of Land Forms. By Professor Geikie,
LL.D., F.R.S. Illustrated. _6s. net_.
RIVER DEVELOPMENT. As Illustrated by the Rivers of North America. By
Professor I.C. Russell. Illustrated. _6s. net_.
VOLCANOES: Their Structure and Significance. By Professor Bonney,
D.SC, F.R.S. Illustrated. _6s. net_.
EARTHQUAKES, In the Light of the New Seismology. By Clarence E.
Dutton, Major U.S.A. Illustrated. _6s. net_.
* * * * *
Life and Works of
CHARLES DARWIN
THE ORIGIN OF SPECIES BY MEANS OF NATURAL SELECTION. _6s. net._
Popular Edition. _2s. 6d. net._ Also in Paper Covers, _1s. net._
DESCENT OF MAN, AND SELECTION IN RELATION TO SEX. With Illustrations.
_3s. 6d. net._
VARIATION OF ANIMALS AND PLANTS UNDER DOMESTICATION. Woodcuts. 2 vols.
_15s. net._ Popular Edition. _7s. 6d. net._
EXPRESSION OF THE EMOTIONS IN MAN AND ANIMALS. With Illustrations.
_9s. net._ Popular Edition. _3s. 6d. net._
VARIOUS CONTRIVANCES BY WHICH ORCHIDS ARE FERTILIZED BY INSECTS.
Woodcuts. _7s. 6d. net._ Popular Edition. _3s. 6d. net._
MOVEMENTS AND HABITS OF CLIMBING PLANTS. Popular Edition. _3s. 6d.
net._
INSECTIVOROUS PLANTS. Popular Edition. _3s. 6d. net._
CROSS AND SELF-FERTILIZATION IN THE VEGETABLE KINGDOM. _9s. net._
DIFFERENT FORMS OF FLOWERS ON PLANTS OF THE SAME SPECIES. _7s. 6d.
net._
FORMATION OF VEGETABLE MOULD THROUGH THE ACTION OF WORMS.
Illustrations. _6s. net._ Popular Edition. _3s. 6d. net._
JOURNAL OF A NATURALIST DURING A VOYAGE ROUND THE WORLD IN H.M.S.
"BEAGLE." With 100 Illustrations. Medium 8vo. _21s. net._ Popular
Edition. With 16 full-page Plates. _2s. 6d. net._
* * * * *
LIFE and LETTERS of CHARLES DARWIN.
With an Autobiographical Chapter. Edited by FRANCIS DARWIN, F.R.S.
With 3 Portraits and Illustrations. 3 vols. 8vo. _36s._
CHARLES DARWIN: An Autobiography. With Selections from his Letters by
FRANCIS DARWIN. Portrait, _7s. 6d. net._ Popular Edition. _2s. 6d.
net._
MORE LETTERS OF CHARLES DARWIN.
A Record of his Work in a Series of hitherto Unpublished Letters.
Edited by FRANCIS DARWIN and A.C. SEWARD. With Portraits. 2 vols. Demy
8vo. _32s. net._
* * * * *
THERAPEUTICS OF THE CIRCULATION.
By Sir T. Lauder Brunton, Bart., M.D., LL.D., F.R.C.P., F.R.S.,
Consulting Physician to St Bartholomew's Hospital. New and Revised
Edition. With Illustrations. 5s. _net_.
In this new edition so much matter has been added that the book has
been practically re-written. It is intended to supplement, and not to
replace, the usual text books dealing with circulation.
THE PREVENTION OF MALARIA. By Sir Ronald Ross, K.C.B., F.R.S., etc.
With Contributions by twenty of the Leading Experts. With
Illustrations. Demy 8vo. 21s. _net_.
"A thoroughly sound and comprehensive treatise; Sir Ronald Ross and
his colleagues have turned out work worthy of their high reputations.
The student of malaria in all respects will find in this work the most
complete exposition of the subject in medical literature."--_Lancet_.
THE HOUSE-FLY: Disease Carrier. An Account of its dangerous activities
and of the means of destroying it. By Leland O. Howard, Ph.D. With
numerous Illustrations. 6s. _net_.
In this book the Chief of the U.S. Bureau of Entomology sets forth
complete information about the fly.
After describing the nature of the common house-fly, its habits and
methods of breeding, he proves his case against it as a carrier of
disease, and goes on to what will be the most interesting section to
most readers--that on remedies and preventive measures. A special
point is made or the possibilities of action by communities, with
suggestions as to organisation, publicity, interesting the children,
and the work of Boards of Health.
* * * * *
WORKS BY EDWARD HALFORD ROSS,
M.R.C.S. (Eng.), L.R.C.P. (Lond.).
Of the John Howard McFadden Researches; the Lister Institute of
Preventive Medicine, London; and sometime Health Officer, Port Said,
the Suez Canal District and Cairo.
THE REDUCTION OF DOMESTIC MOSQUITOS. Instructions for the use of
Municipalities, Town Councils, Health Officers, Sanitary Inspectors,
and Residents in Warm Climates. Demy 8vo. 5s. _net_.
THE REDUCTION OF DOMESTIC FLIES.
With Illustrations. Demy 8vo. 5s. _net_.
LONDON: JOHN MURRAY, ALBEMARLE STREET, W.
End of Project Gutenberg's Form and Function, by E. S. (Edward Stuart) Russell