Part I. The Darwinian Theory. =Cloth, $2.00.=

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A

MECHANICO-PHYSIOLOGICAL

THEORY OF

ORGANIC EVOLUTION

BY

CARL VON NAeGELI

SECOND EDITION

CHICAGO

THE OPEN COURT PUBLISHING CO.

1914

COPYRIGHT, 1898

BY THE OPEN COURT PUBLISHING CO.

CHICAGO

PREFATORY NOTE.

Mr. V. A. Clark, as a student in horticulture in the University

of Vermont, first undertook a critical examination of Naegeli's

_Mechanico-Physiological Theory of Evolution_ as a part of his regular

junior work. After a half year's study and the preparation of a short

thesis, Mr. Clark had become so far intimate with Naegeli's work as to

make it seem best for him to continue the study through his senior year.

This study involved extended translations from the text, including

Naegeli's _Summary_, which, considering its difficult accessibility

to American students, has been chosen for publication. The work has

been done chiefly by Mr. Clark, but has all been under my immediate

supervision, and I have given the whole matter a final restudy and

revision. Those who have had any experience with similar work will know

how impossible it is that all mistakes should have been avoided, and it

would be a kindness to the translators if readers would point out any

defects, in order that they may be corrected.

F. A. WAUGH.

University of Vermont,

July 1, 1898.

A MECHANICO-PHYSIOLOGICAL

THEORY OF ORGANIC

EVOLUTION.

SUMMARY.

In this summary I shall in general pursue a course the reverse of that

which my main work follows.[A] I shall proceed from the primitive,

unorganized condition of matter and endeavor to show how organized

micellar substance has arisen in it, and how, from this micellar

substance, organisms with their manifold properties have arisen.

Since such a synthesis of organisms out of known forms of matter and

force is still far removed from a conclusion strictly in accord with

physical law, the process becomes comprehensible and obvious only by

exact knowledge of the discussion that has preceded. Although the

synthetic method reveals more clearly the weaknesses of the theory

than do analytic investigations, yet I considered it helpful to

make this presentation in order to give a clearer idea of the

mechanico-physiological theory, and at the same time to test its

worth.

[A] See Appendix, Translators' Notes.

1. FORMATION OF UNORGANIZED BODIES (CRYSTALS).

When separated and promiscuously moving molecules of any substance in

solution or in a melted condition pass into the solid form by reason of

removal of the causes of separation and motion (warmth or solvent), they

arrange themselves into solid masses impermeable to liquids. These

minute bodies grow by accretion, and when molecular forces are permitted

to act undisturbed, assume the regular outer form and inner structure of

crystals. The number of crystals, their size, changes of form and

growth, all depend on external conditions.

2. FORMATION OF LIVING ORGANIZED (MICELLAR) BODIES.

Certain organic compounds, among them albumen, are neither soluble,

despite their great affinity for water, nor are they fusible, and hence

are produced in the micellar form. These compounds are formed in water,

where the molecules that arise immediately adjoining each other arrange

themselves into incipient crystals, or micellae. Only such of the

molecules as are formed subsequently and come in contact with a micella

contribute to its increase in size, while the others, on account of

their insolubility, produce new micellae. For this reason the micellae

remain so small that they are invisible, even with the microscope.

On account of their great affinity for water the micellae surround

themselves with a thick film of it. The attraction of these micellae for

matter of their own kind is felt outside this film. Hence the micellae

with their films unite themselves into solid masses permeated with

water, unless other forces overcome attraction and re-establish a

micellar solution (as in albumen, glue, gum), where the slightly moving

micellae show a tendency to cling together in chain-like and other

aggregations. Very often there are found, especially in albumen, half

liquid modifications intermediate in fluidity between the solid masses

and the micellar solution.

The internal and external constitution of micellar bodies depends

essentially on the size, form and dynamic nature of their micellae, since

these efficients condition the original arrangement of the micellae and

the insertion in proper order of those formed later. External conditions

have slight influence on structure, and affect outer form chiefly in so

far as they can mechanically hinder free development.

The micellae of albumen or plasma are susceptible of the greatest

diversity of form, size and chemical composition, since they originate

from unlike mixtures of various albumen compounds, and besides are mixed

with various organic and inorganic substances. For this reason the

plasma behaves, both chemically and physically, in many unlike ways, and

in consequence of the variable relation of the micellae to water, the

plasma shows all degrees of micellar solution up to quite solid masses.

3. SPONTANEOUS GENERATION. LIFE. GROWTH.

If molecular forces are so combined in an inorganic substratum that

spontaneous formation of albumen takes place, then by the combination of

the micellae the primordial plasma masses of spontaneous generation are

given. Within these plasma masses the production of albumen goes on more

easily under the influence of their molecular forces than in the liquid

without. Hence the compounds present in the organic substratum and

capable of forming albumen enter preferably into the masses of plasma,

and by intussusception of micellae of albumen, cause growth. Here life

exists in its simplest form. (See page 47.)

Spontaneous generation presupposes the origin of plasma-micellae from

molecules, and hence cannot be brought about by solutions of albumens or

peptones, since these are micellar solutions. Life presupposes the

intussusception of plasma-micellae; hence it ceases as soon as the

arrangement of micellae is so far disordered by injurious influences that

that process of growth becomes impossible.

The resulting organism must be perfectly simple, a mass of plasma with

micellae as yet unarranged, because any organization without a preceding

organizing activity is inconceivable. For this reason known organisms

cannot have orginated spontaneously; a kingdom of simpler beings must

have preceded them (_Probien_--the sub-organic kingdom).

The growth of the masses of plasma continues as long as the conditions

of nutrition are favorable. If these become unfavorable, a resting

period (latent life) or partial or total death occurs, according to

circumstances (as lack of nutritive material, lowering of temperature,

comparative exsiccation). The growth of plants and animals is nothing

else than the continuation of the growth begun in the primordial plasma.

This growth still continues wherever the primordial plasma exists.

4. PARTIAL DEATH OF THE INDIVIDUAL: REPRODUCTION.

Since the primordial masses of plasma continue to attract nutritive

materials indefinitely and apply them to growth, the nutritive materials

are used up in one place and another and the substance which is no

longer nourished is in great measure disintegrated. A general condition

of equilibrium now sets in, in which the viable plasma masses continue

to gain just as much in growth as there is dead plasma broken down and

changed back into the original nutritive materials.

In the primordial condition this balancing process is irregular and

accidental and remains so even later in many of the lowest organisms.

Little by little it becomes phylogenetically more regular by individuals

attaining to a more definite size and term of life, while only the germs

detached from them remain viable. This phenomenon known as reproduction

has a double origin.

_A._ The portions of primordial plasma that grow to a more considerable

size as soft, half-liquid masses break up by the mechanical action of

external circumstances into smaller portions of indefinite number and

size. This typifies irregular and accidental reproduction of the lowest

order.

In the offspring of the primordial plasma division becomes gradually

more and more regular as a result of the increasing organization of the

substance, and especially as a result of the formation of an envelope

about it, till finally in the microscopically small masses, which are

now called cells, division into two parts always appears, after these

masses have grown to perhaps double their original size. After division

the two halves separate from each other and represent independent

individuals.

In the further course of phylogeny the division of the cells into two

parts takes place regularly. But the cells remain united to each other

and form multicellular individuals, which increase by cell division and

which at times in the lowest stages are divided at regular intervals

into smaller individuals, perhaps even at last into single cells, but

from which there are periodically given off cells that develop as germ

cells into new multicellular individuals.

_B._ Another phenomenon which appears in the primordial plasma or its

immediate offspring is the death of the greater part of the plasma under

certain unfavorable conditions of nutrition, while the smaller part

continues to be nourished at its expense and in that case remains viable

during the dormant period.

In the offspring this phenomenon gradually becomes free cell formation,

which takes place before the resting stage or before the death of many

unicellular and multicellular organisms, and which forms germ cells from

a part of the contents of the parent cells.

The formation of germ cells by cell division (_A_), or by free cell

formation (_B_) is reproduction of the organism. The germ cells are the

elements in which the life and growth of the parental individual are

continued.

5. MORPHOLOGY OF THE IDIOPLASM IN GENERAL.

The larger part of the unarranged, soft and homogenous primordial

plasma, which grows by intussusception, becomes watery soma-plasm, with

unarranged and easily movable micellae. The smaller part is converted in

the course of phylogeny into idioplasm, in which at certain favorable

points the micellae that are being stored up under the influence of

molecular forces arrange themselves into groups by similar orientations,

and hence form bodies of less water content and greater solidity. Each

body of idioplasm consists originally of only one group of micellae,

which, however, necessarily breaks up with increasing additions into

several groups. On account of the dynamic influence of the groups of

micellae upon their own growth, they become in part more distinct and

more definitely separated, in part again differentiated by new irregular

intussusception. This phylogenetic process is continued indefinitely,

by which the combination of forces produces a new configuration, and

conversely, by which a new configuration produces a new combination of

forces, so that the body of idioplasm merely takes on a continually

increasing complexity of configuration by the action of the internal

forces--that is, by the molecular forces of the micellae of the albumen

under the influence of which growth proceeds. This constitutes the

_automatic perfecting process_ or progression of the idioplasm, and

entropy of organic matter. (See p. 47.)

The above described phylogenetic perfecting process of the idoplasm,

which operates through internal causes, is scarcely affected by

differences of nutrition and by climatic conditions influencing

nutrition. On the other hand all those external forces which act as

stimuli during a long period of time in an unvarying manner have a very

noticeable influence on the intussusception of micellae in the idioplasm

and on the molecular processes going on among the micellae. The action of

stimuli determines the particular structure of the groups of micellae

added under the direction of the perfecting process. Thus the

configuration of the idioplasm becomes continually more and more complex

and at the same time assumes a local adaptation corresponding to

external conditions. This constitutes adaptation of the idioplasm.

6. FUNCTION OF THE IDIOPLASM IN GENERAL.

The unarranged micellae of the albumen of the spontaneously generated

plasma are as yet in no way superior to the unorganized condition from

which they have arisen, except in this that under the influence of their

molecular forces the formation of similar new albumen micellae follows

more easily. But as by the further action of molecular forces

idioplasmic bodies are formed with groups of smilarly oriented micellae,

the molecular forces of these micellae amount by summation to molar

forces and thereby new chemical processes are introduced; plastic

products are formed from plasmic and non-plasmic materials, and molar

movements are introduced. And since idioplasmic bodies are formed under

the influence of external stimuli, their plastic products always appear

with a definite character of adaptation to environment.

Then, as the idioplasmic body becomes continually more complex in the

further course of phylogeny, and consists of a greater number of groups

of micellae differing from each other, the organisms become more complex

and differentiate into a greater number of parts, because each group of

micellae of the idioplasm produces its specific effect with regard to

inner structure, outer form, and function.

7. DETERMINANTS: THEIR ORIGIN AND DISAPPEARANCE.

Since a particular cluster or group of micellae of the idioplasm produces

a particular phenomenon in the organism, the former is designated as the

determinant (_Anlage_, see p. 49) of the latter. Thus the organism must

contain at least as many determinants in its idioplasm as there are

different phenomena in its inheritable ontogeny; and if new phenomena

appear in it, new clusters of micellae must previously have been

introduced into the idioplasm, or the orientation and arrangement of

clusters already present must have been changed. The formation of such a

determinant, whether it concerns the perfecting of the organism or its

adaptation to environment, always proceeds very slowly, and as a rule

has no effect before its completion. Hence along with perfected

determinants the idioplasm always contains growing and incomplete

determinants.

If a phylogenetic line comes under the influence of other external

conditions and other external stimuli than those which have hitherto

acted upon it, a new and corresponding arrangement of the micellae

appears phylogenetically in the idioplasm. At the same time the other

adaptation determinants remain either undisturbed, or the new

determinant is formed at the expense of related determinants which are

already present and which may at last entirely vanish. Hence along with

growing and complete determinants the idioplasm always contains likewise

weakened and vanishing determinants. From the fact that a phylogenetic

race is thrown repeatedly among different external conditions, it may at

last unite in its idioplasm a large number of developing, mature, and

vanishing adaptation determinants. This number is noticeably increased

if in consequence of interbreeding a fusion of related idioplasms take

place.

8. DEFINITE NOTIONS WITH REGARD TO THE MORPHOLOGY OF THE IDIOPLASM.

Since in the phylogenetic development of the plasma the thicker

idioplasm is differentiated from the more fluid soma-plasm (Sec. 5), the

former has the tendency by nature to assume a reticular arrangement. The

strands of this network consist, in conformity with their origin, of

parallel rows of micellae extending lengthwise. These rows of micellae

are combined into more or less complex arrangements, so that the cross

section of the strand represents the configuration of the idioplasm.[B]

[B] Naegeli makes his idioplasm ramify throughout the organism in

unbroken continuity, much like a system of nerves in the higher

animals. This idea with Naegeli was purely speculative. It was

known that the protoplasm is in connection throughout the

organism, but it has been proved more recently that only the

somatic protoplasm is thus connected. The part in which the

essential nature of the organism is contained is localized

in the nucleus and hence might properly be designated as

nucleoplasm, as Weismann suggests. If the idioplasm is

localized in the nucleus, it cannot be continuous throughout

the system, as Naegeli assumes. But this objection applies only

to a detail of the theory and does not affect the fundamental

conception,--that of a portion of the protoplasm which is

differentiated from the rest and represents a definite molecular

structure which determines the specific nature of the

organism.--_Trans._

Each ontogeny (individual) begins in a minute germ cell, in which a

small quantity of idioplasm is contained. In the cell divisions, by

which the organism grows, the idioplasm divides into as many parts as

there are single cells, while it continually increases in quantity in a

corresponding degree. The ontogenetic increase of the idioplasm takes

place by length growth of the strands--that is, by intercalation of

micellae in each row of cells of the strands, which thereby grow in

length without changing the configuration of the cross section.[C]

Accordingly, each strand of idioplasm contains all the determinants that

the particular individual has inherited in the germ cell, and each cell

of the organism is idioplasmatically qualified to become the germ cell

of a new individual. Whether this qualification may be realized depends

upon the nature of the soma-plasm. In the lower plants this power

belongs to each individual cell; in the higher plants many cells have

lost it; in the animal kingdom it is possessed in general only by cells

normally set apart as asexual or sexual reproductive cells.

[C] Hence, according to Naegeli, every cell of the organism has

idioplasm of identical structure. This at once suggests the

objection, how can the idioplasm, for instance, of a pollen

grain be the same as that of a leaf? Identical idioplasms should

always produce identical structures. Naegeli attempts to explain

this difficulty by attributing the different results to

different "conditions of tension and movement," i.e., a

dynamical difference between the idioplasms of the different

parts of the organism. (_Abstammungslehre_, p. 53.)

This idea of differences of structure being due to dynamic

rather than to material causes plays a considerable part in

Naegeli's theory, but is the point on which he speaks with least

certainty--in fact with a noticeable hesitation. He does not

clearly explain the phrase "conditions of tension and movement,"

nor does he give a convincing explanation of the known phenomena

as results of the action of dynamic influence.

Naegeli is not the only one who posits dynamic rather than

material differences as to the basis of diversities of

structure. More recently, Cope has built up a system of

evolution founded largely on this idea.--_Trans._

The continued phylogenetic formation of the threads of idioplasm takes

place by growth in the cross section, which contains the sum of all the

determinants and changes in general only when new rows of micellae are

intercalated. But the rows of micellae of the idioplasm join closely to

each other, according to their thickness, so that only rarely new rows

can enter, and then only at those definite places where the cohesion is

less strong and hence is overcome. The cohesion varies irregularly

because the configuration of the cross section, conformably to its

origin, is never regular; the disruptive tensions are brought about by

the unequal growth in length of the individual rows of micellae. Dynamic

influences have a decisive effect upon cohesion and disruptive tensions.

The groups of micellae of the configuration already obtained exercise

these dynamic influences upon each other; and these dynamic influences

can be modified by stimuli from without.

The idioplasm continually alters its configuration with its growth in

successive ontogenies, but comparatively very slowly, so that it makes a

minute advance from the germ of one generation to the germ of the next.

The summation of these increments of advance through a whole line of

evolution represents the race history of an organism, since the latter

is connected only by its idioplasm in unbroken continuity with the

micellar beginning of its race.

9. DEFINITE NOTIONS REGARDING THE FUNCTION OF THE IDIOPLASM.

A plasmic substance causes definite chemical and physical changes only

when it is present in a certain condition of motion. The peculiar agency

which the idioplasm has in each ontogenetic stage of development and in

each part of the organism depends on the activity of a definite group of

micellae in the cross section of the strand or of a complex of such

groups, while this local stimulus controls the chemical and physical

processes by dynamic influence and by transmission of a specific mode of

motion, even to a microscopically small distance.

The effective stimulus in a plasmic substance is dependent on its own

nature and the influence which it receives from without. Which group of

micellae in the idioplasm receives the stimulus depends on the

configuration, on the preceding stimuli and on the position in the

individual organism in which the idioplasm is found. The determinants

have arisen one after another during the whole period of evolution from

the primordial cell. The configuration of the idioplasm is a character

of phylogeny and the determinants in it have by nature the tendency to

develop in the order in which they were formed. Further, since the

ontogeny begins as a unicellular organism with the formation of a germ

cell, that determinant of the idioplasm comes first to development,

which has developed in the unicellular ancestor. Just so the succeeding

stages of ontogeny depend for the time being on the development of the

determinants having their origin in the corresponding stage of

phylogeny. Both causes acting together--the phylogenetic configuration

of the idioplasm and the successive morphological stages of development

of the individual conditioned on it--necessarily result in the ontogeny

being the repetition of the phylogeny.

If the whole remaining line of idioplasmic determinants in an ontogeny

has reached development, the development of the germ-forming

determinants finally follows as well from the configuration of the

idioplasm as from the nature of the organism. The individual is capable

of reproduction and the new ontogenies begin in the reproductive cells.

10. TRANSMISSION OF IDIOPLASMIC DETERMINANTS IN LOCAL VARIATION AND IN

FECUNDATION.

The automatic progressive or perfecting transformation of the idioplasm

is probably active in all stages of development, and proceeds regularly

in all parts of the organism, because the idioplasm preserves its

configuration at all times and places during the ontogeny. External

stimuli impign upon the organism usually at a definite point, but they

not only effect a local transformation of the idioplasm but also

reproduce themselves in a dynamic manner in the entire idioplasm, which

is in unbroken connection throughout the whole individual. The idioplasm

is thus changed everywhere in the same manner, so that the germ cells

that are given off at any point feel and inherit the effects of those

local stimuli.

In the formation of the germ cells in sexual reproduction, the

idioplasms of both parents must come into contact with each other,

whereupon there results either a material union and formation of a mixed

idioplasm or perhaps rather a dynamic action; and through these agencies

there is produced a remodeled form which is, however, exactly equivalent

to the combined idioplasms entering into it. Fertilization by diosmose

of the spermatic substance is impossible.[D]

[D] This assertion is a direct corollary from the structure of

the determinants and the idioplasm. If the idioplasm of the

fertilizing cell were to pass through the membrane about the

ovum by osmosis, its organized structure would be

lost.--_Trans._

In the idioplasm of a germ cell arising from the crossing of unlike

individuals the micellar rows of the individual determinants have

sometimes an intermediate constitution and produce characteristics in

the organism which are intermediate between the characteristics of the

parents. Sometimes the micellar rows derived from the father and mother

respectively lie side by side unchanged in the idioplasm of the

offspring in distinct groupings and may reproduce in the organism their

respective characteristics side by side, or only one of them may

develop, while the other remains latent.

On account of the union of both idioplasms as the result of fecundation,

two sexually mature organisms are the more able to form with each other

a viable germ cell, the nearer they are genetically related--that is,

the more nearly the male and female idioplasms correspond in their

configuration and chemical nature, because in this case the micellar

arrangements are best suited to each other, and the idioplasm of the new

fertile germ cell receives its most suitable nourishment from the

mother. If, however, self-fecundation or the closest in-and-in breeding

often yields products of less virility and is avoided by nature, this

is the result of injurious influences which make themselves felt later

on. This is because incompatibilities may be present in too closely

related idioplasms and these are sources of weakness in unrestricted

development. The more complicated is the idioplasm, the oftener this

occurs, whereas absolute lack of crossing is not detrimental to the

simplest (asexual) organisms.

11. ACTION OF EXTERNAL INFLUENCES.[E]

The environment provides the organism above all with force and matter

for its life processes. It causes no permanent variation and has only an

ontogenetic significance, if the limits of the idioplasmic elasticity

are not exceeded; it maintains the growth and metabolic assimilation of

the individual, and conditions individual (not hereditary) differences,

which constitute "nutrition varieties." (See page 30.) These appear as

the direct results of operating causes.

[E] In order to explain adaptations Naegeli assumes that external

influences, if acting at the same point in a given manner for a

long time, may induce slight adaptive variations which are

perpetuated and increased. On the important subject of

adaptation in general Naegeli is almost diametrically opposed to

Darwin and Weismann. Naegeli assigns to the principle of utility

a very limited sphere; Weismann regards adaptation as

all-powerful. According to Naegeli, the organic world would have

become much what it is, if natural selection and adaptation had

performed no part in the operations of nature. He aptly says,

that natural selection prunes the phylogenetic tree, but does

not cause new branches to grow. He allows that the principle of

selection is well suited to explain the adaptation of organisms

to their environment and the suitableness and physiological

peculiarities of their structure, but he asserts that in the

definiteness of variation of plants and in their progressive

differentiation there is evidence of a higher and controlling

perfecting principle.--_Trans._

When the stress of environment exceeds the limits of idioplasmic

elasticity, its influence brings about permanent variations, which are

imperceptibly small, it is true, in the single individual, but which,

when the stimulus is active for a long period of time in the same

manner, increase to perceptible magnitude. These variations are

inheritable in the phylogenetic sense and contribute to the formation of

varieties and species; they always appear as the results of more or less

secondary reactions which make their appearance with stimuli exerted by

external causes.

External stimuli exerted on the organism are reproduced in the

idioplasm. Since the stimulus is discontinued with each change of the

ontogeny and only the idioplasm persists, permanent variations are

produced only in the idioplasm by those conditions that produce visible

transformations in the mature organism.

The phylogenetic action of external stimuli gives the definite character

of adaptation to the idioplasm as it becomes more complex from inner

causes and probably these external stimuli have the power to alter this

impress only as new idioplasm is automatically formed.

If an external cause acts continuously upon a phylogenetic line, the

corresponding variation of the idioplasm reaches, after a time, a

maximum, and thus comes to an end, either because the nature of the

substance permits no new rearrangement or because the stimulus is no

longer active. The cessation of the stimulus results from a micellar

rearrangement which indicates the character of the adaptation. If the

action of the stimulus lasts for only a short time, the incipient

rearrangement of the idioplasm stops, or proceeds independently on

account of the impulse received, and the determinant becomes capable of

development, even after the impulse has long ceased to act.

Since various intervening transpositions follow upon a stimulus in the

organism, the final result which appears as a reaction may turn out

variously. The same external causes may, according to the nature of the

organism and other circumstances, have very unlike variations as a

result. But the internal rearrangement produces in a definite case very

definite variations.

On account of the various intermediate steps it is often difficult to

discover the external cause of a given adaptive variation. In many cases

we recognize it without difficulty in a definite mechanical process or

in warmth, light or evaporation. For the most part the stimulus awakens

in the organism merely a want, which the reaction of the organism

endeavors to supply. Hence it appears that want or lack alone is able to

bring about such reactions. Moreover, in the sphere of sex, electric(?)

attractions and repulsions co-operate between the idioplasmic

determinants to produce phylogenetic variations.

The adaptations of the fully developed organism, which are the results

of external influences, consist either only of a specific molecular

character (irritability), by virtue of which the individual is capable

of responding to those influences with temporary or permanent phenomena,

or they consist of finished arrangements. The latter have, in general, a

double function: either they protect the organism from external

influences whose results they are, or they place it in a condition to

apply such environmental influences to their advantage. The

preponderance of the one or the other led to the development of the

plant or the animal kingdom. In the one case the primordial plasma

formed in the cellulose cell wall a stimulus-proof covering. On account

of this cell membrane being insensible to stimuli, adaptations in the

plant kingdom were restricted essentially to the spheres of nutrition

and reproduction. In the other case the irritability and mobility of the

primordial plasma increased so that it was placed in a condition to

avoid the irritant or make it serviceable by accommodating itself to it.

The cells sensible to irritants led in the animal kingdom to the

formation of organs of sense and the nervous system.

12. CONDITIONS OF PHYLOGENETIC DEVELOPMENT OF THE DETERMINANTS. ATAVISM.

In the primordial condition, formation and development of the

determinants coincide, since the plasma constituting the organism

possesses the capability of growing by intussusception of new micellae

and of changing this growth through the action of inner and outer

causes. But as the primordial plasma differentiates into idioplasm and

soma-plasm, the formation of determinants consists in the transformation

of the idioplasm, while the development of determinants consists in the

production of soma-plasm and of non-plasmic substances under the

influence of the idioplasm.

Only the mature determinant is able to develop, especially if, at the

same time, a related and heretofore active determinant must be forced

back into the latent condition. But the determinant of an absolutely new

form of adaptation, which does not take the place of a preceding one,

must develop enough before it can become outwardly manifest, for it to

be possessed of a sufficient amount of molecular energy to render its

activity possible. For this reason the characteristics of the developed

organism change abruptly, notwithstanding the fact that the

transformation of the idioplasm has proceeded very gradually.

The configuration of the idioplasm becomes continually more complex

through the automatic action of the perfecting process, and by this

means the organism ascends to higher stages of organization. Hence the

viable determinants of organization or perfection are always overtaken

after a certain time by that movement and forced into the latent

condition. They then become continually weaker, and are at last

completely destroyed. Only in the first period after their becoming

latent can such determinants pass again into a developmental condition

and thus allow the organism to revert to the next preceding stage of

organization.

Since the configuration of the idioplasm, which becomes more complex

from internal causes, always assumes a definite character of adaptation

in consequence of the action of external causes, the adaptation

determinants capable of development may become more and more weakened

and at last latent when other external causes produce other adaptation

determinants. But these determinants may be revived by the renewed

activity of the former causes, and thus rendered capable of development.

Hence the organism may show the most various reversions with respect to

its adaptations. But in such reversions the earlier forms never quite

return, because in the meanwhile the idioplasm has changed somewhat in

consequence of its automatic progress, and therefore lends to the

adaptations which assume the earlier character a somewhat different

expression.

13. ONTOGENETIC DEVELOPMENT OF THE DETERMINANTS.

Since the capability of the primordial plasma to grow is the original

and only vital quality (_Anlage_), the whole ontogeny in this first

stage consists in the growth of the detached parts to the adult size. In

the same way the development of the determinants in all the following

stages is nothing more than the growth of the substance detached as a

germ cell after the manner of the changes in the character of the

idioplasm in the course of phylogeny. In this manner all determinants

may in the lower stages of organization reach development, but in the

higher stages an increasing number of them must remain latent.

Among the viable determinants there are some that develop

unconditionally during each ontogenetic period; there are also

alternative determinants of which one or the other unconditionally

develops; lastly, there are some that develop only under favorable

circumstances. Which of two alternative determinants shall develop

depends sometimes on internal, sometimes on external causes, according

as the specific determinant has arisen phylogenetically through the

action of internal or external causes. Climatic and nutritive influences

especially affect the appearance of indefinitely developing

determinants. Just so, when a determinant may develop repeatedly (as is

so common in the plant kingdom) it depends especially on nutrition

whether the corresponding phenomenon is repeated at intervals of greater

or less length. A weakened determinant is sometimes temporarily

developed by the operation of a definite stimulus.

If the integrity of the organism sustains an injury in consequence of

abnormal interferences, determinants develop exceptionally at unusual

points. The process is induced by accumulation of nutritive matter and

by external stimuli under the force of necessity, to which the injured

organism is sensible.

14. ESSENTIAL NATURE OF THE ORGANISM.

The essential nature of a thing is the sum total of its causes and

effects. Organisms arise from a germ cell which consists of idioplasm

and in turn they produce like germ cells. Their nature depends also on

their idioplasm, _i.e._, on the sum total of their idioplasmic

determinants. Observation of organisms, even in their fullest life

history, gives us an imperfect and even false conception of their true

nature. This is because observation reveals only the outer gross

characters, and even these in a modification dependent upon accidental

effects of nutrition, and does not reveal the finer characters founded

in molecular physiology and morphology, and especially the characters

latent in the idioplasm.

For the examination of idioplasmic differences we are restricted to

visible characters. Hence a knowledge of the nature of an organism

presupposes a complete investigation of its characters in their

succession during the whole ontogeny. The results must, however, be

tested and completed by comparison with other organisms and by the most

comprehensive experimental procedure, possible, (as by culture under

various conditions, and crossing with nearer and more remote relatives).

The characteristics of nutrition varieties and accidental crosses must

be separated from specific characteristics by experimental procedure,

and latent determinants must be brought out by the same means.

15. REPRODUCTION, AND RELATION BETWEEN PARENTS AND OFFSPRING.

Reproduction is nothing more than a transition from one generation to

the next following, mediated by the idioplasm of the germ cell. In

asexual (monogenic) reproduction there is continuity of the same

idioplasm. Therefore the parent continues in the offspring its specific

life, as the stem continues its specific life in the branch. All the

peculiarities conditioned by the idioplasm remain unchanged in the

offspring. The latter, as the immediate continuation of the preceding

ontogeny, starts from the point at which the germ cell left it, so that

immediately after the germ cell is separated at the close of the

ontogeny or before, the offspring passes at one time rapidly through

the whole ontogeny, at another only the remainder or a part of it (the

latter in alternation of generations and in asexual propagation of

phanerogams).

In sexual (digenic) reproduction the formation of the germ cell is

brought about by the union in equal parts of both parental idioplasms.

The offspring is the organism resulting from the union of the force and

matter of the parents, and represents in its nature the united

continuation of their ontogenies. The characteristics of development of

the child depend however on the viability of the determinants of the

mingled idioplasms in which a new equilibrium has been formed. Hence if

the child bears more resemblance to the father or to the mother, it

follows that some of the inherited determinants develop while the others

remain latent. If the child has certain visible characteristics more

marked than either parent, it becomes possible only by the development

of determinants which had previously been latent. The fact that the

mother furnishes the germ cell with nutritive plasm and that she

nourishes it for a considerable time does not increase the number of

maternal determinants nor their capability of development.

If two corresponding characters, one derived from the father, the other

from the mother, come into conflict in sexual reproduction, the one or

the other, or even a third alternative characteristic, which heretofore

was present as a latent determinant, may develop in the child. But also

both parental characters may appear at once and in various combinations.

Whether the development follows in the one way or the other depends on

the strength of the individual determinants, on the kind of their

idioplasmic arrangement, and on their agreement with the nature of the

newly formed idioplasm.

16. HEREDITY AND VARIATION.

If heredity and variation are defined according to the true nature of

organisms, they are only apparent opposites. Since idioplasm alone is

transmitted from one ontogeny to the next following, the phylogenetic

development consists solely in the continual progress of the idioplasm

and the whole genealogical tree from the primordial drop of plasma up to

the organism of the present day (plant or animal) is, strictly speaking,

nothing else than an individual consisting of idioplasm, which at each

ontogeny forms a new individual body, corresponding to its advance.

In this idioplasmic individual the _automatic_ or _perfecting variation_

is always active, so that the idioplasm of a phylogenetic line always

grows by propagation of the determinants contained within it, as a tree

grows larger through its whole duration of life by branching. On the

other hand the _adaptation variation_ caused by external stimuli is

present only in those periods of the phylogenetic line in which the

idioplasm, and together with this the individual, do not possess the

obtainable maximum of adaptation to their environment for the time

being. Both of these variations of the idioplasm take place so slowly

that only after a long series of generations do the new determinants

become capable of developing and revealing themselves in the

transmutation of visible characters.

Aside from the phylogenetic variations already named, which take place

according to the measure of ontogenetic growth, the idioplasm undergoes,

as a result of crossing, as well as in changes of the ontogeny,

_gamogenic variations_ which may be designated as stationary, since in

the mingling of sexually different idioplasms there arise only new

arrangements of determinants already present, but no new formation of

determinants takes place. Hence in this way arise also new combinations

of developmental characteristics.

As a result of external injurious influences, abnormal variations, or

_pathological variations_, appear in the idioplasm. These consist of

disturbances of equilibrium, which take place also without new formation

of determinants. Thereby the determinants already present are caused to

develop in abnormal relations, and mostly in reversions.

Apart from the inheritable variations of the idioplasm just enumerated,

and the transformations of visible characters involved in it, the

soma-plasm and the non-plasmic substances experience, by the influence

of nutrition and climate, greater or less variations, which constitute

_nutrition varieties_, and since the idioplasm remains unaffected in

general, last only so long as the causes which called them forth.[F]

[F] Naegeli, like Weismann, arrives at the conclusion that

acquired characters are not inherited. He was not content,

however, to rest the generalization upon purely speculative

grounds, but undertook the experimental demonstration. After

seventeen years of work by himself and son, especially upon

several species of Hieracium, he satisfied himself that his

theory was true to the facts. We all know now how far he fell

short of settling the question.--_Trans._

If we have in mind the inner nature of the organism, there is, properly

speaking, no such specific phenomenon as heredity, since the

phylogenetic line is a continuous idioplasmic individual. In this sense

heredity is nothing more than the persistence of organized substance in

a movement in which variations are automatically induced, or the

necessary transition of one idioplasmic configuration into the next

following. It is present, not only among plant and animal individuals

which are ontogenetically separated, but also everywhere within these

individuals, where individual parts (cells, organs) follow each other in

time. Hereditary phenomena are those that necessarily pass over to

following generations, and in general those that are located in the

idioplasm, since non-idioplasmic substance can be hereditary only

through a limited number of cell generations.

Variations and heredity are generally estimated, not according to the

inner nature of the mature individuals, but according to their relation

in successive generations, since heredity is assumed when the

ontogenetic characters remain the same, and variation when previously

latent characters become visible. But these phenomena belong to another

department of science; they concern the possibility and reality of

development of the idioplasmic determinants.

17. VARIETY, RACE, MODIFICATION.

From the multifarious variations of organisms proceed various categories

of kinship. _Varieties_ arise by extremely slow changes in the idioplasm

due to the perfecting process and adaptation. Since these are

conditioned by the same causes, they follow in all individuals of the

same variety in uniform manner. Varieties are uniform, entirely constant

under the most various external conditions, in general cross only with

difficulty with related varieties, are not varied by accidental crosses,

and persist through geological periods. Varieties belong to feral nature

rather than to culture; they can assume all possible modifications

without injury to their specific characteristics, but can show no

distinctions of races, for all beginnings of race formation are

destroyed by free intercrossing. They differ from species only in that

they are to be designated as more closely related species, or species as

more remotely related varieties. Every other distinguishing

characteristic is wanting.

_Races_ arise from gamogenic or pathological variations of the

idioplasm. In the former case they presuppose crossing between related

varieties or species, in the latter case an increased sensibility and

weakening of the idioplasm. Very often both causes co-operate, since

crossing follows more easily when the idioplasm is weakened by hurtful

influences and since the irritability and weakening of the idioplasm

increases if crossing has preceded. Race formation begins in single

individuals. Among several individuals it begins in various directions

because the causes are different and hence may display a great

multiformity. Races are distinguished by more or less abnormal

characteristics; they arise quickly--often in a single generation--and

present various degrees of stability. This stability is insured to some

extent only by the strictest in-and-in breeding. All races disappear

through crossing, likewise many races that have arisen from pathological

variations disappear even in sexual reproduction (in self-fecundation).

Races belong exclusively to cultivation, where they can develop and

exist protected from free intercrossing.

While varieties and races arise by progressional or stationary variation

of the idioplasm, _modifications_ are produced by such influences of

nutrition and climate as act only on the soma-plasm and the non-plasmic

substances, and hence do not give rise to inheritable characters in the

organism. Modifications persist only so long as their causes, and under

other environments immediately pass over into the modifications

corresponding to them. The transition is completed in the lowest plants

during a limited number of cell generations; in an individual of the

higher plants on the same stem during the growth of a single year. Each

variety and each race appears clothed in a definite modification, and

can change it within a range peculiar to itself.[A]

[G] The distinctions which Naegeli here erects are, of course,

purely arbitrary, and his definitions are suitable for use only

in his own thesis.--_Trans._

18. SOCIAL AND INDIVIDUAL ORIGIN OF SPECIES.

The species arises neither from the _nutrition variety_ nor from the

_race_; it is always a more advanced variety, and hence species

formation is identical with variety formation. Cause for variation and

consequently for variety formation is always shown, either when,

environment remaining the same, the automatic variation of the idioplasm

has advanced so far that the ontogeny is raised to a higher grade of

organization and division of labor, or when external stimuli act for a

sufficiently long time in a manner not in harmony with the previous

adaptation. Hence various varieties arise easily from a uniform kinship,

when these are thrown among unlike external influences by local

separation, because in the separated places on the one hand the

automatic evolution proceeds with unequal rapidity, and on the other

hand adaptation takes place unequally.

But in general different varieties arise socially from a uniform

kinship. This is because the related individuals living together are

unequally stimulated on account of the great inequality of external

influences which may exist at the smallest distances; and also because

with slight individual differences unlike reactions often follow upon

the same external influences. If identically similar individuals are

equally inclined to very different reactions toward the same stimulus,

sometimes the direction of the first variation decides the character of

the adaptation and therefore the nature of the variety, because the

variation, when once begun, progresses unswervingly even under somewhat

different circumstances.[H] Hence divergent variations are found growing

together in all places, which variations have begun at different though

neighboring points by transformation of the idioplasm and are soon

intermingled on account of the easy dissemination of seed.

[H] It is interesting to compare this statement with Weismann's

recent theory of Germinal Selection.--_Trans._

The social formation of varieties is not in general interrupted by

crossing, a process which governs only the formation of races. It is

confirmed according to experience by the universally recurring fact that

several beginnings of the most closely related varieties appear

together not only in the same region, but even at the same points, while

the geographical distribution of the more marked varieties and of

related species offers no conclusion as to their origin, but only as to

the last great migration of the plant world, because they arose before

this period, as indeed appears from their distribution.

Just as different varieties arise simultaneously from one kinship at the

same place, the same variety may arise in places far separated, when the

analogous external exciting causes occasion an identical transformation

in the idioplasm. The experimental proof lies in the fact that like

beginnings of varieties often appear at great distances from each other.

An apparent social origin of varieties is indicated, when, after having

come together in migration, they first develop the unlike determinants

which they have gained in various locations. An apparently individual

origin of the same or different varieties is indicated, when the

formation of the determinants take place at one and the same place, but

their development follows only after the kindred has been scattered by

migration.

19. GENERAL RELATION OF THE PHYLOGENETIC LINES IN THE ORGANIC KINGDOMS.

Since the nature of an organism is contained in the sum of its

idioplasmic determinants alone, the evolution of a phylogeny consists in

the evolution of the idioplasm. This is perceived from the succession

of the visible ontogenetic characteristics which in general run parallel

with it. The idioplasm varies in two ways: (1) by an _automatic

perfecting process_; (2) by _adaptation to environment_.

By virtue of the _automatic variation_ of the idioplasm the ontogenies

of a phylogenetic line attain to a continually more complex organization

and greater differentiation of function. In this differentiation,

however, only the qualitative differences are of importance;

quantitative and numerical gradations may be disregarded. The more

complex admits of more combinations than the simpler; hence if a

phylogeny reaches a higher stage by automatic evolution it may branch

into several lines, of which each appears as the continuation of the

parent stock.

Since _adaptive variations_ depend only on the transmutations of

environment, an organism may rise to a higher organization and division

of labor by continually adapting itself to the changed environment. But

the organism may also change its adaptation while it remains at the same

stage of organization. And since the adaptive variation is quickly

perfected as compared with automatic evolution, although extremely

slowly as compared with the duration of the ontogeny, an organization

may change its adaptation several times while it remains at the same

grade of organization and division of labor. Since there are also

numerous different kinds of adaptation, a phyletic line may divide at

each point into several adaptive forms, which appear in the taxonomic

system as species, genera, often even as whole families, while in other

cases various degrees of organization have appeared in one family.

20. LAWS OF EVOLUTION OF THE PLANT KINGDOM.

In the sub-organic kingdom, which precedes the plant and animal

kingdoms, (see page 5), there are gradually formed from the

spontaneously generated plasma independent cells with their

characteristic properties, _i.e._, growth by intussusception of micellae,

formation of a plasmic cuticle, and a non-plasmic membrane about the

same, division of the cells, separation of the cells thus formed, and

free cell formation within the cell contents. These properties are

inherited from the sub-organic kingdom by the plants and animals which

follow in the next stage of phylogeny. The evolution of the plant

kingdom proceeds through the following regular processes, which continue

to operate through the entire phylogenetic series.

_Law of Phylogenetic Combination._--The simplest of all plants are cells

of round form, which grow and reproduce themselves by division, budding

or free cell formation. From the fact that the younger generation of

cells, instead of separating from each other and growing to independent

plant individuals, remain united with each other, multicellular plants

arise from unicellular. The same transformation of the reproductive

cells into non-separable tissue cells is repeated several times in

multicellular plants and serves to enlarge the individual. There is

manifested in this phylogenetic process the tendency of the plant to

combine in the higher stages into one complex whole those parts which in

the lower stages tend to be independent. A similar unifying tendency is

revealed also in those plant members which have arisen by

differentiation and represent a system only by their being connected at

certain points. These combine in the higher stages and form ultimately

continuous tissues.

_Law of Phylogenetic Complication or Ampliation, Differentiation and

Reduction._--The cells, and, in general, the parts of plants which lie

near each other in space or follow upon each other in time, are always

alike in the lower stages. By differentiation they become unlike, so

that the sum of the functions which at first fall to the lot of all

parts without distinction now is shared among the individual parts. By

this means each part can perform its own special function so much the

better. Differentiation is repeated in the course of the phylogeny,

since at first all parts of an ontogeny diverge into two or more parts,

then the parts of these parts divide again, etc. Along with this process

of division another process is always active, which, as it were,

prepares the way for the former, namely, ampliation, by virtue of which

the growth of the whole ontogeny or of single stages of it undergoes a

quantitative increase, so that an organ acquires a greater number of

cells, and an individual a greater number of organs. After this increase

in number of parts in a stage of ontogeny, differentiation follows as

far as the nature of the functions permits, by the parts most separated

passing into each other by intermediate gradations. By the further

phylogenetic process of reduction the intermediate forms are suppressed.

At last only the extreme products of differentiation lie near each other

in space or follow upon each other in time; and these products are as

limited in quantity and number as possible.

Along with the above named phylogenetic processes, which take place by

the automatic increase of the idioplasm, external influences are always

active. These lend to the organism at times a local stamp corresponding

to its environment, and follow the law of adaptation.

21. ALTERNATION OF GENERATIONS IN RELATION TO PHYLOGENY.

Since the simplest plants are cells and the more complex ones are formed

from cells, a whole phylogenetic line may be regarded as a series of

cell generations following one after another. In the lowest forms all

cell generations are like each other; in all others they show

differences which become continually greater and more numerous. Thus

alternation of generations in cells exists, because the successive

generations become more and more complicated at each succeeding period.

Among these periods the ontogenetic period or ontogeny embraces all

generations from one cell to the return of the exactly similar kind of

cell. In the lowest forms of cell differentiation the cells of

successive generations are all independent; the ontogenetic period

consists of a cycle of generations of unicellular plants. Later the cell

generations of an ontogeny are united by parts into plant individuals;

the ontogenetic period consists of a cycle of multicellular and

unicellular, or only of multicellular plant generations. If all the cell

generations of an ontogenetic period have been united into a single

individual, the successive plant generations are alike and alternation

of generations has ceased.

The unlikeness of the generations arises either from inner causes of

temporary differentiation alone, or by temporary differentiation which

receives a definite imprint by the change of seasons. But in the latter

case the characteristic of adaptation is again lost in the course of the

phylogeny and alternation of generations follows then without regard to

the season. If the given adaptation is united in the lower plants with

alternation of generations during the ontogenetic periods, one of the

unlike plant generations is repeated an indefinite number of times

(repetitional generation), while the other unlike plant generation

appears only once and then at the beginning of the resting stage and

remains latent in the form of a resting spore till the beginning of the

next period of generation. With this peculiar transition generation,

which has arisen in the lower stages asexually, and in the following

higher stages by the union of a male and a female cell, and which hence

is hermaphrodite, there are generally associated later two other single

generations--_viz._, a generation preceding and one following the

hermaphrodite, the former as a sex-producing generation, the other as a

sex-produced generation.

The phylogenetic significance of the alternation of generations consists

in its representing a transition stage from the unicellular to the

simpler multicellular and from the latter to the more complex

multicellular plants. The plant generations of any phylogenetic stage

increase by ampliation, become unlike by differentiation in time

(alternation of generations), and unite in a plant individual, whose

unlike ontogenetic stages correspond to the unlike plant generations of

the earlier ancestral series.

22. MORPHOLOGY AS THE SCIENCE OF PHYLOGENY.

All organic phenomena belong, according to their causes, to two

different classes: (1) Those belonging to one group are the results of

external influences in each ontogeny and are not inherited; they

represent nutrition varieties, are experimentally demonstrable, and

constitute the subject matter of experimental physiology. (2) The others

are inherited and again transmitted; they belong to the physiology of

the idioplasm. This subject is mainly occupied with the origin of the

determinants, hence with the formation of varieties and species. It is

not the subject of experiment, and constitutes the phylogeny or the

physiology of the formation of determinants. A sub-division of this

subject is occupied with the development of the determinants already

present, hence with the formation of races. It is elucidated especially

by experiments in crossing and may be designated as the physiology of

the development of the determinants.

The morphological phenomena which find their application in taxonomy,

belong exclusively to phylogeny. Their ontogenetic history does not

explain their true significance; this can be known only in a

phylogenetic way by comparison of one phenomenon with those phenomena

from which it has arisen in the course of evolution.

23. PLANT CLASSIFICATION FROM THE STANDPOINT OF PHYLOGENY.

Spontaneous generation has taken place at all times and in all places,

in as far as the necessary conditions were concurrently present. (See

page 47). After spontaneous generation the automatic phylogenetic

evolution begins and advances constantly. Consequently the phylogenetic

line rises from time to time to higher stages of organization and

division of labor, but dies of old age if the automatic perfecting

process ceases. The phylogenetic lines of organisms now living have

therefore an unequal age; those of the most highly developed plants and

animals had their origin in the earliest periods of organic life, those

of the lowest organisms in the most recent periods. Hence no general

genetic relation exists among lines now living; only those that are

nearly related and have reached approximately equal stages of

organization may be regarded as branches of the same phylogenetic stock.

A phylogenetic plant system does not exist in fact, but only in figure.

If genetic relation between two races is assumed, either as a reality or

as a symbol, the degree of relationship is determined in a theoretically

exact manner by the number and length of the phylogenetic steps which

are found either between them both or between them and the common

starting point, according as races belong to the same or collateral

lines. The fact that two organisms belong to the same line of descent is

recognized from the ontogeny of the higher including the ontogeny of the

lower.

Since only a proportionately small number of known forms can appear as

types of the supposed stages of evolution, only a few phylogenetic

lines, and these only in a general way, may be established, on account

of the great incompleteness of the present plant world. Such a line

proceeds from the green filamentous algae through the liverworts to the

vascular plants. Among the phanerogams, apparently so numerously

represented, only phylogenetic series of individual organs can be

ascertained, but no phylogenetic series of families. A phylogenetic

system of phanerogams is not to be hazarded in the roughest outline.

Even the relative rank of the two chief divisions of the angiosperms,

the monocotyledons and dicotyledons, is a matter of question, as also

which family in each of these divisions is to be considered the most

perfect.

APPENDIX.

TRANSLATORS' NOTES.

_The Mechanico-physiological Theory of Evolution_,

(_Mechanisch-Physiologische Theorie der Abstammungslehre_),

by Carl von Naegeli, was published in Munich and Leipsic in 1884 in a

large octavo volume of 822 pages, including two large appendices. The

_Abstammungslehre_ proper, including the summary, occupies 552 pages,

and constitutes, in its way, one of the most important contributions to

theoretical biology. It is difficult to understand how a work of so much

consequence should have received such comparatively small notice in this

country, especially as Naegeli's theories seemed calculated by nature to

appeal much more strongly to American students than do, for instance,

those of Weismann, who has been studied ten times as much as Naegeli.

This is doubtless due, in part, to the fact that we have had no English

translation of Naegeli's work, a circumstance much to be regretted.

The foregoing translation of the summary from _Abstammungslehre_

goes but a small way toward making Naegeli's theories accessible to

English-reading students, but it will, at least, be better than nothing.

The work covers a great range of subjects, all, however, having a

certain relationship to each other. In the main part of the book the

discussion is presented in the following order: (1) Idioplasm as bearer

of the inheritable determinants; (2) Spontaneous generation; (3) Causes

of variation; (4) Determinants and visible characters, in which the

origin and function of the determinants is presented; (5) Variety, race,

"nutrition variety," heredity and variation; (6) Criticism of the

Darwinian theory of natural selection, in which the author urges seven

objections to that theory; (7) Laws of evolution of the plant kingdom;

(8) Alternation of generations from the standpoint of phylogeny; (9)

Morphology and classification as phylogenetic sciences; (10) A

comprehensive summary of the whole work, a translation of which is

given in the foregoing pages.

In the first part of the work Naegeli sets forth his micellar theory of

the structure of organized bodies. This is one of his most important

contributions to science. Until recent years it has been the only theory

given in botanical text-books. At the present time its only competitor

is Strasburger's lamellar theory, and even this has not superseded

Naegeli's work to any great degree.

The reader who may not be familiar with the micellar theory will find

the general idea from the following brief sketch adapted from Vines's

_Plant Physiology_:

"Naegeli's micellar theory was developed from his study of

organized bodies, especially of cell walls and starch grains.

From the behavior of organized substance toward water absorbed

by it, he concluded that water does not penetrate into the

micellae, but only among them, thus merely separating them more

from each other. He reasoned that if water should penetrate into

the micella, its structure would be disintegrated. Hence he

argued that organized bodies consist of solid micellae, which,

with their respective films of water, are held together by: (1)

The attraction of the micellae for each other, which varies

inversely as the square of the distance. (2) The attraction of

the micellae for water, which varies inversely as some higher

power of the distance. (3) The force which holds together the

ultimate chemical molecules of which each micella consists.

"Since the swelling up of organized bodies does not take place

equally in all three dimensions of space, and on account of

their double refraction, Naegeli inferred that in form the

micellae are crystals, probably parallelopipedal, with

rectangular or rhomboidal bases."

The law that "bodies attract each other with a force which varies

inversely as the square of the distance," has been proven only in its

application to the heavenly bodies. Naegeli has applied this law to

molecules, unsupported, however, by any evidence other than that of

analogy. On the other hand, there is evidence that molecules do not

invariably act according to this law.

Spontaneous generation (p. 4) was an important item in Naegeli's

doctrine, and might almost be said to be fundamental to it, although it

is not really necessary to the internal perfecting principle, which may

be regarded as the chief feature of the Mechanico-Physiological Theory.

Up to 1865 Naegeli believed in the spontaneous origin of many fungi, and

thought that it could be demonstrated. He was obliged to abandon the

experimental evidence, but to the close of his life held the views of

abiogenesis presented in the accompanying translation.

The characteristic and most interesting feature of the

Mechanico-Physiological Theory is certainly Naegeli's conception of an

automatic perfecting principle (_Autonome Vervollkommnung_). This

conception may be briefly outlined as follows:

1. The essential part of the reproductive plasm, termed idioplasm, since

it divides and passes over from generation to generation, in higher as

well as in lower organisms, has a continuous or "immortal" existence.[I]

[I] Naegeli's idioplasm corresponds in many respects, though by

no means in all, to Weismann's germ-plasm. Weismann's idea of

continuity or "immortality," which has been so widely noticed,

is set forth with equal clearness, though with less emphasis, by

Naegeli.

2. During this continuous life the idioplasm goes through a development

of its own, just as an individual organism goes through a certain cycle

of development during its individual life. This development consists in

a constantly increasing complexity of structure and differentiation of

function.

3. This development is automatic, resulting from internal forces or

movements, (_Vervollkommnungs-bewegungen_).

4. As a result of the increasing complexity of structure in the

idioplasm the entire organism, which in each generation rearises

therefrom, becomes, from generation to generation, more and more complex

with greater and greater differentiation of function. Thus the

progression of the idioplasm controls the phylogeny of the race. It

marks out the course of evolution.

5. Since, according to Naegeli, new life with new idioplasms, may arise

wherever and whenever the necessary conditions combine, the present

organic world is not made up from branchings of a single original

idioplasm, but each race or group may have its own specific idioplasm;

and, since this has its own characteristic structure and its own

specific internal perfecting forces, it passes through its own peculiar

evolution, carrying with it its own depending race of organisms.

The fact that animals and plants at the present time show such various

degrees of organization is also accounted for on the last supposition,

for those of lowlier organization are merely of more recent origin and

have not progressed so far in idioplasmic development.

This automatic perfecting principle has been the mark of much criticism.

Some have confounded it with the mystical _nisus formativus_, or

formative principle of preceding theorists. But, as Weismann remarks,

Naegeli's phyletic force is conceived as a thoroughly scientific

mechanical principle. Naegeli has simply made application in the organic

world of the principle of entropy, as stated in the mechanical theory of

heat. Naegeli himself also compares his internal perfecting principle to

mechanical inertia. He says, "the force of evolution once started in a

given direction, tends to continue in the same direction. This

constitutes the law of inertia in the organic world."

* * * * *

Two other matters remain to be noticed. The first of these is Naegeli's

use of the German word _Anlage_. We have been unable to give a perfectly

satisfactory translation of this word in its technical meaning. We have

received some comfort, though but little help, from the experience of

the translators of similar works. Selmar Schoenland, in translating from

Weismann, renders it variously as "germ," "germ of structure," "germ (of

Naegeli)," "germ of Naegeli," "Naegeli's preformed germ of structure,"

"preformed germs," "tendency." Another translator renders the word as

"constitutional element." The translation, "determinant," which we have

selected is an appropriation of an analogous but not absolutely

identical technical term from Weismann's _Germinal Selection_. The use

of the word in this connection is open to the objection that it has

previously been used technically for a somewhat different idea by

another author. M. C. Potter, in his translation of Warming's

_Systematic Botany_, following Dr. E. L. Mark, renders the word _Anlage_

as "fundament." Dr. H. C. Porter, in his translation of the _Bonn

Text-Book of Botany_, renders the same word as "rudiment."

In general the word Anlage means beginning, plan, disposition to

anything, and hence involves the ideas of origin, organization and

tendency. Sanders defines the word in one of its meanings as: "The act

of planning or beginning anything; the act of laying the foundation of

any work intended to be carried on toward completion, in order that from

the beginning made, a definite thing may be developed or may develop

itself"; (_i.e._, to determine, in the sense of limiting to a particular

purpose or direction, hence determinant). "Also, the thing begun or

planned, considered as the basis and germ of the further development of

that which has already originated."

In its restricted use as applied to organisms it would mean "germ," in

the sense of embryonic starting point. More specifically, it is a

portion of plastic, organized substance, functioning as an individual

and containing potentially an elemental organ plus a formative power. In

Naegeli's own words, "There exists an essential difference between the

substance of a mature organism which does not possess the capability of

further development, and the substance of an egg, which does possess

this capability. By virtue of this difference the egg-substance is

characterized as the _Anlage_, or germ of the mature organism. All

characteristics of the adult condition are potentially contained in the

ovum."

Naegeli was not the first to assume the existence of a unit of

organization intermediate between the molecule and the cell. E. B.

Wilson, in his _The Cell in Inheritance and Development_, states the

case as follows:

"That the cell consists of more elementary units of

organization, is indicated by _a priori_ evidence so cogent as

to have driven many of the foremost leaders of biological

thought into the belief that such units must exist, whether or

not the microscope reveals them to view. The modern conception

of ultra-cellular units, ranking between the molecule and the

cell, was first definitely suggested by Bruecke in 1861.

"This idea of ultra-cellular units is common to most

morphologists and physiologists. We are compelled by the most

stringent evidence to admit that the ultimate basis of living

matter is not a single chemical substance, but a mixture of many

substances that are self-perpetuating without their loss of

specific character."[J]

[J] For a fuller discussion of the notion of these hypothetical

units of organic existence, see Weismann's Germinal Selection,

(Open Court Publishing Co., Chicago, 1896), especially the foot

note, page 230.

Naegeli's _Laws of Evolution_ are also worth special notice. As stated in

the body of _Abstammungslehre_ they are as follows:

1. Asexual reproductive cells which arise by division, remain united and

become tissue cells.

2. Asexual reproductive cells which arise by budding, instead of

separating, become cell branches or branched cell threads.

3. Reproductive cells which arise by free cell formation become bodies

which form a part of the cell contents.

4. Parts of a plant which arise by differentiation lie side by side and

form a body of web-like or tissue-like structure.

5. A definite and previously limited growth continues, or a definite

formation of parts of an ontogeny which has previously been present but

once, is repeated. (Ampliation.)

6. The parts of an ontogeny become dissimilar, since the functions which

were previously united become differentiated and since new dissimilar

functions are produced in the various parts. This differentiation is

either one of space between the parts of the ontogeny that appear near

each other, or one of time between those that are derived from each

other.

7. Parts which have become dissimilar by differentiation undergo a

reduction, in which the intermediate forms are suppressed and at last

only the qualitatively dissimilar forms with qualitatively dissimilar

functions remain.

8. The environment in which plants live operates in different ways,

directly as a stimulus or indirectly as a felt necessity and by this

means lends to their forms and activities a definite expression of time

and place, and thus brings about different adaptations. These become

permanent through heredity, but are again gradually lost if other

adaptations supersede them.

Laws 1 to 4 may be expressed as one--the law of combination: Similar

parts that are wholly or partly separated have the tendency to unite

more and more completely and intimately into one continuous tissue.

The laws of ampliation (5), differentiation (6), and reduction (7), may

be summarized in one as follows: While increasing in size the similar

parts of an ontogeny become internally dissimilar and the dissimilarity

increases as the transition forms of the dissimilar parts vanish. Hence

only the extreme forms remain.

* * * * *

It may also interest the reader to know that Naegeli was the first to

propose the general theory of cell formation as accepted at the present

day.

BRIEF STATEMENT OF THE WORK OF THE OPEN COURT PUBLISHING COMPANY

If one asked for a brief description of the work of the Open Court

Company, one would probably get the answer that the Company publishes

books and articles on Science, Religion, and Philosophy. That is not

quite exact; for that describes the ideal to which the Open Court

Company is continually striving rather than the actual work it is doing.

The ideal is Religion on a firm basis of Science, a Science of

Philosophy, and a Philosophy of Science: the only path which can lead to

this great ideal synthesis is the detailed and careful study of

sciences, religions, and philosophies.

It was this ideal that prompted the late Mr. Edward Carl Hegeler of La

Salle, Illinois, in the United States of America, to found a Company to

publish books with the object of establishing ethics and religion upon a

scientific basis. Such ideals are as old as philosophy itself. Among

modern philosophies, that founded by Comte tried, probably in the most

explicit fashion of all, to found a religion on the basis of positive

science; and at one time it appeared likely to have a lasting success.

But it is now quite plain that no philosophy which hopes to be permanent

can neglect history or put itself into uncritical opposition to the

systems that have for centuries expressed some of the dearest and

highest aspirations of mankind. It is unprejudiced and fearless

historical and critical investigation--non-sectarian in the widest

sense--in both religion, science, and philosophy, that must go before

any satisfactory synthesis. This is a great part of the work of the Open

Court Company.

Let us consider what non-sectarianism means. We cannot, for example,

isolate a single domain of science in a particular country and at a

particular time--say, mechanics in England in the eighteenth

century--and hope to make of it a thoroughly complete object of study.

In natural science, for example, we make conventional divisions simply

with the object of saving labor when dealing with the huge mass of

material that experience offers. But the narrowest specialist knows that

all workers in science, religion, and philosophy seek the Truth; and

that the Truth is bounded neither by space nor by time nor by man-made

divisions. A man may rightly conclude that he stands little chance of

finding out very much of the Truth, and so he may voluntarily limit his

view to a certain roughly defined domain of facts and thoughts, and

become, for example, what is called a "biologist," a "physicist," a

"higher critic," or, if he thinks that he may discover rather more of

the Truth, a "philosopher."

And let us carry a clear understanding of a lofty aim into religion as

well. It is our duty, as rational beings, to be non-sectarian. It is not

a merit to allow ignorance to blind us to the glimpses of Truth that we

sometimes get from prophets, poets, and priests of other religions and

other philosophies than our own. If we think that there is more truth or

sacredness in our own, let us use every means to make this sacredness or

this truth appear evident to others. But, in justice, let us also

fearlessly discuss other religions and philosophies, and discover their

greater merits, if any, as compared with our own. If, after careful

investigation, we arrive at the belief in the truth or falsehood of

anything in these religions or philosophies, let us state our grounds

for believing so in the fullest possible way. Only by so doing can we

fulfil the duties of being true to ourselves and helpful to others.

Sometimes the work of a critic is said to be "merely destructive." This

idea rests on a most harmful misunderstanding. Criticism consists not

only in the pointing out of error, but in the pointing out of truth as

well. Error is simply a psychological condition of blindness to the

truth; and the discovery of errors committed by other people or

ourselves is not--as many superficial people like to say--the pulling

down of a structure already raised, unless an error can be called a

structure which is built out of the fictions of our imagination which

have no objective existence. Criticism often enables us to discover more

of the Truth, and nobody can do more than _discover_ Truth: nobody

_creates_ Truth, any more than Columbus created America.

Nowadays all intelligent men and women agree that all knowledge must be

subjected to criticism, and the best men and women act on these beliefs.

The books and magazines published by the Open Court Company are intended

to help these men and women.

We will dwell a little longer on the subject of religion, because it is

in religion that the majority of us have the one region of ideals above

our bodily needs. It is rare, though of course not unknown, that Science

or Philosophy satisfies the spiritual needs--the purest of human

cravings. Nowadays, most of us realize that an anti-scientific attitude

of religion is impossible. If there were an opposition between "science"

and "religion," there would be no question as to which side would be

victorious. More particularly during the last seventy years, "religion,"

conscious of the opposition which a rather crude doctrine which was

called "science" had towards it, has been gradually, and often somewhat

ludicrously, trying to bring itself more into conformity with that

"science." The result is painful to the student of human nature; though

it has its amusing sides, just as had the militant denial, on the part

of those who were "on the side of the angels" about fifty years ago, of

certain deductions from facts. What is called a "conflict between

religion and science" always has ended in a victory for "science" and an

agnosticism which ousted religion. And thus many see that it is

desirable that the matured results of science should enter into the

fabric of our religious convictions. For the realization of this

purpose, the Open Court Company publishes two periodicals, _The Monist_,

a quarterly magazine devoted to the philosophy of science, and _The Open

Court_, an illustrated monthly devoted to the science of religion and

the religion of science. In addition, the Open Court Company publishes

books that directly or indirectly advance its aim--books on Philosophy,

which, in contrast with the old metaphysicism, lay the foundations of a

philosophy of science; books on the history of philosophies; books on

mathematics and other lines of thought which are indispensable for a

rational and scientific conception of the world; books that have a

bearing on the doctrine of Evolution; books on the history of Religions,

especially on the development of Christianity and on Higher Criticism;

and books on Comparative Religion, on Psychology, on Education, and on

Ethics. Above all, in all the works careful, sympathetic, and scholarly

criticism is aimed at. Criticism is the joint result of love of Truth

and independence of thought; rightly understood, it is not only a

preliminary to a work of synthesis, but it is part of synthesis itself.

No synthesis, in fact, is more than a discovery of Truth: from past

history we know that syntheses have often blinded men to the Truth,

though that was naturally not their intention.

On the subject of independence of thought it may be proper shortly to

refer to the work of Dr. Paul Carus, who has been, since the end of

1887, closely associated with the Open Court Company and its

publications. Only two things need be said here. In the first place, it

was owing to the need he felt for keeping his independence of thought

that he resigned a post in Germany and came, first to England and then

to America. In the second place, his views, which are also, broadly

speaking, the views for which the Open Court Company works, may be

characterized both as monism and positivism, though his philosophy

differs considerably from Haeckel's monism, which is practically

materialism, and even more so from the French positivism of Comte and

from agnosticism, its English equivalent. In his philosophy, _form_

plays the most important part. Form is the significant feature of both

objective existence and subjective thought. Matter and energy only

denote reality, but form characterizes quality. Science traces form, and

the nature of all things, the human character included, is constituted

by form. In the formal sciences again, that which is the core of their

usefulness as general propositions is the character of _anyness_, the

use of which justifies the method of generalization. Here lies the root

of the kinship of Dr. Carus's philosophy with modern logic, and allows

him to reconstruct the old artistic and religious ideas upon a new and

modern ground. In this sense, he himself has characterized his

philosophy as a _philosophy of form_.

A Partial List of Books in the

OPEN COURT SCIENCE SERIES

PROBLEMS OF SCIENCE

BY FEDERIGO ENRIQUES

Authorized translation by Katherine Royce, with an introduction

by Josiah Royce. =Pp. 375. Price, $2.50.=

"The end for which we ought to strive today is a scientific education,

which shall enable the workers in any field whatsoever to understand

better how the object of their own research is subordinated to more

general problems."

The author is professor of projective geometry and geometric drawing in

the University of Bologna, and is one of the most conspicuous of

contemporary Italian scientists.

The Primary Factors of Organic Evolution By E. D. Cope

=Illustrated. Cloth, $2.00 net=

The Soul of Man By Paul Carus

An investigation of the facts of physiological and experimental

psychology. =Illustrated. Cloth, $1.50 net; paper, 85c.=

Plant Breeding By Hugo De Vries

Comments on the experiments of Nilsson and Burbank.

=Illustrated. Cloth, gilt, $1.50 net=

The Rise of Man By Paul Carus

A sketch of the human race. =Illustrated. Boards, cloth back,

75c net=

Species and Varieties, Their Origin and Mutation By Hugo De Vries

Edited by D. T. MacDougal. =Price, $5.00 net=

The Mutation Theory By Hugo De Vries

Experiments and observations on the origin of species in the

vegetable kingdom. (2 vols.) Translated by Prof. A. B. Farmer

and A. D. Darbishire. =Numerous illustrations, colored plates.

Cloth, per volume $4.00 net.=

Intracellular Pangenesis By Hugo De Vries

Including a paper on fertilization and hybridization. Translated

from the German by C. Stuart Gager. =Cloth, $3.00 net.=

On Memory and the Specific Energies of the Nervous By Ewald Hering

System

New edition, including "The Theory of Nerve Activity."

=Price, $1.00; paper, 30c.=

Psychology of the Nervous System By Paul Carus

An extract from the author's larger work, "The Soul of Man."

=Price, 30c.=

The Psychology of Reasoning By Alfred Binet

Translated by Adam Gowan Whyte. =Cloth, 75c net=

Has the Psychological Laboratory Proved Helpful? By L. M. Billia

Translated from the French by Lydia G. Robinson. =Pp. 16. Paper,

15c net.=

A Mechanico-Physiological Theory of

Organic Evolution By Carl von Nageli

Summary. =30c.=

Experiments on the Generation of Insects By Francesco Redi

Translated from the Italian edition of 1688 by Mab Bigelow.

=Illustrated. Cloth, $2.00 net=

Science and Faith, or Man as an Animal, and Man

as a Member of Society, with a Discussion on

Animal Societies By Paul Topinard

Translated by T. J. McCormack. =Price, $1.50 net=

A First Book in Organic Evolution By D. Kerfoot Shute

Written especially for the use of students. =Illustrated, seven

colored plates, 2d ed. Cloth, $1.25; paper, 60c net=

On Germinal Selection as a Source of Definite

Variation By August Weismann

Translated by T. J. McCormack. =Paper, 30c=

Popular Scientific Lectures By Ernst Mach

Translated by T. J. McCormack. =Illustrated. $1.50 net; paper,

60c net=

Contributions to the Analysis of the Sensations By Ernst Mach

Translated by C. M. Williams. =Price, $1.25 net=

Space and Geometry in the Light of Physiological,

Psychological and Physical Inquiry By Ernst Mach

Translated by T. J. McCormack. =Cloth, gilt top, $1.00 net=

The History and the Root of the Principle

of the Conservation of Energy By Ernst Mach

Translated by Philip E. B. Jourdain. =Cloth, $1.25 net=

On the Inheritance of Acquired Characters By Eugenio Rignano

Translated by Basil C. H. Harvey. With an appendix "On the

Mnemonic Origin and Nature of Affective Tendencies." =Cloth,

$3.00 net=

Darwin and After Darwin By George J. Romanes

An exposition of the Darwinian theory and a discussion of

post-Darwinian Questions. =Three volumes, $4.00 net.=

Part I. The Darwinian Theory. =Cloth, $2.00.=