APPENDIX.

The Mechanico-physiological Theory of Evolution, (Mechanisch-Physiologische Theorie der Abstammungslehre), by Carl von Nägeli, was published in Munich and Leipsic in 1884 in a large octavo volume of 822 pages, including two large appendices. TheAbstammungslehreproper, 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 Nägeli'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 Nägeli. This is doubtless due, in part, to the fact that we have had no English translation of Nägeli's work, a circumstance much to be regretted.

The foregoing translation of the summary fromAbstammungslehregoes but a small way toward making Nägeli'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 Nägeli 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 At the present time its only competitor is Strasburger's lamellar theory, and even this has not superseded Nägeli's work to any great degree.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'sPlant Physiology:

"Nägeli'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 micellæ, 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 micellæ, which, with their respective films ofwater, are held together by: (1) The attraction of the micellæ for each other, which varies inversely as the square of the distance. (2) The attraction of the micellæ 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, Nägeli inferred that in form the micellæ are crystals, probably parallelopipedal, with rectangular or rhomboidal bases."

"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, Nägeli inferred that in form the micellæ 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. Nägeli 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 Nägeli'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 Nägeli 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 Nägeli'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]

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 Nägeli, 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 ownpeculiar 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 mysticalnisus formativus, or formative principle of preceding theorists. But, as Weismann remarks, Nägeli's phyletic force is conceived as a thoroughly scientific mechanical principle. Nägeli has simply made application in the organic world of the principle of entropy, as stated in the mechanical theory of heat. Nägeli 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 Nägeli's use of the German wordAnlage. 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 Nägeli)," "germ of Nägeli," "Nägeli'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'sGerminal 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'sSystematic Botany, following Dr. E. L. Mark, renders the wordAnlageas "fundament." Dr. H. C. Porter, in his translation of theBonn 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 Nägeli's own words, "There exists an essential difference betweenthe 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 theAnlage, or germ of the mature organism. All characteristics of the adult condition are potentially contained in the ovum."

Nägeli was not the first to assume the existence of a unit of organization intermediate between the molecule and the cell. E. B. Wilson, in hisThe Cell in Inheritance and Development, states the case as follows:

"That the cell consists of more elementary units of organization, is indicated bya priorievidence 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 Brücke 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]

"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]

Nägeli'sLaws of Evolutionare also worth special notice. As stated in the body ofAbstammungslehrethey 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 Nägeli was the first to propose the general theory of cell formation as accepted at the present day.

FOOTNOTES[A]See Appendix, Translators' Notes.[B]Nägeli makes his idioplasm ramify throughout the organism in unbroken continuity, much like a system of nerves in the higher animals. This idea with Nägeli 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 Nägeli 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.[C]Hence, according to Nägeli, 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. Nägeli 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 Nägeli'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.Nägeli 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.[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.[E]In order to explain adaptations Nägeli 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 Nägeli is almost diametrically opposed to Darwin and Weismann. Nägeli assigns to the principle of utility a very limited sphere; Weismann regards adaptation as all-powerful. According to Nägeli, 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.[F]Nägeli, 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.[G]The distinctions which Nägeli here erects are, of course, purely arbitrary, and his definitions are suitable for use only in his own thesis.—Trans.[H]It is interesting to compare this statement with Weismann's recent theory of Germinal Selection.—Trans.[I]Nägeli'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 Nägeli.[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.

[A]See Appendix, Translators' Notes.

[B]Nägeli makes his idioplasm ramify throughout the organism in unbroken continuity, much like a system of nerves in the higher animals. This idea with Nägeli 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 Nägeli 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.

[C]Hence, according to Nägeli, 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. Nägeli 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 Nägeli'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.Nägeli 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.

This idea of differences of structure being due to dynamic rather than to material causes plays a considerable part in Nägeli'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.

Nägeli 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.

[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.

[E]In order to explain adaptations Nägeli 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 Nägeli is almost diametrically opposed to Darwin and Weismann. Nägeli assigns to the principle of utility a very limited sphere; Weismann regards adaptation as all-powerful. According to Nägeli, 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.

[F]Nägeli, 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.

[G]The distinctions which Nägeli here erects are, of course, purely arbitrary, and his definitions are suitable for use only in his own thesis.—Trans.

[H]It is interesting to compare this statement with Weismann's recent theory of Germinal Selection.—Trans.

[I]Nägeli'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 Nägeli.

[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.

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 conditionof 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 thandiscoverTruth: nobodycreatesTruth, 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 ourreligious 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, andThe 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 Hæckel's monism, which ispractically materialism, and even more so from the French positivism of Comte and from agnosticism, its English equivalent. In his philosophy,formplays 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 ofanyness, 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 aphilosophy of form.

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 EvolutionBy E. D. Cope

The Primary Factors of Organic Evolution

By E. D. Cope

Illustrated. Cloth, $2.00 net

The Soul of ManBy Paul Carus

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 BreedingBy Hugo De Vries

Plant Breeding

By Hugo De Vries

Comments on the experiments of Nilsson and Burbank.Illustrated. Cloth, gilt, $1.50 net

The Rise of ManBy Paul Carus

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 MutationBy Hugo De Vries

Species and Varieties, Their Origin and Mutation

By Hugo De Vries

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

The Mutation TheoryBy Hugo De Vries

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 PangenesisBy Hugo De Vries

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 SystemBy Ewald Hering

On Memory and the Specific Energies of the Nervous System

By Ewald Hering

New edition, including "The Theory of Nerve Activity."Price, $1.00; paper, 30c.

Psychology of the Nervous SystemBy Paul Carus

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 ReasoningBy Alfred Binet

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

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 EvolutionBy Carl von Nageli

A Mechanico-Physiological Theory of Organic Evolution

By Carl von Nageli

Summary.30c.

Experiments on the Generation of InsectsBy Francesco Redi

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 SocietiesBy Paul Topinard

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 EvolutionBy D. Kerfoot Shute

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 VariationBy August Weismann

On Germinal Selection as a Source of Definite Variation

By August Weismann

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

Popular Scientific LecturesBy Ernst Mach

Popular Scientific Lectures

By Ernst Mach

Translated by T. J. McCormack.Illustrated. $1.50 net; paper, 60c net

Contributions to the Analysis of the SensationsBy Ernst Mach

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 InquiryBy Ernst Mach

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 EnergyBy Ernst Mach

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 CharactersBy Eugenio Rignano

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 DarwinBy George J. Romanes

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.Part II. Post-Darwinian Questions: Heredity and Utility.Cloth, $1.50.Part III. Post-Darwinian Questions: Isolation and Physiological Selection.Cloth, $1.00.

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.

Part II. Post-Darwinian Questions: Heredity and Utility.Cloth, $1.50.

Part III. Post-Darwinian Questions: Isolation and Physiological Selection.Cloth, $1.00.

An Examination of WeismannismBy George J. Romanes

An Examination of Weismannism

By George J. Romanes

Cloth, $1.00 net; paper, 40c net.

Footnotes have been moved to the end of the text just after the appendix.

Other than that, printer's inconsistencies in spelling, punctuation, and ligature usage have been retained.

Back to Index Next