A book by Charles Darwin, in which a revolutionary explanation for the phenomenon of evolution was given, involving the natural selection as the main evolutionary force. This books is for biology what De revolutionibus... is for physics and astronomy - it created the fundaments of a modern science, and provided a general paradigm for this field.

Evolution, biology, and indeed all of science, are often criticized for being too mechanical, and taking the soul out of life. The Origin of Species expresses very well the sense of wonder and awe that is imparted by careful study of the Natural world. This is exemplified in the often quoted (see anything by Stephen Jay Gould) last sentence, which reads

"There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved."

"A man who dares to waste an hour of life has not discovered the value of life."
-Charles Darwin

The Theory

Since its introduction, the concept of evolution has been one of the most popular, yet most misunderstood themes of biology to the general public. Before the late 1850s, the most subscribed to idea of how life came to be as it is was divine creation. However, that would soon change.

The idea that life evolves was expressed by several eighteenth and nineteenth scientists. However, without a reasonable explanation for evolution, other scientists of the time opposed the idea vehemently. It wasn’t until 1859 that a naturalist from England, one Charles Darwin, provided convincing proof that species do evolve and suggested a means by which they do so.

To present his ideas, Darwin wrote a book in which he detailed his studies and observations and gave proof for the hypotheses he made. This rather technical book was called On the Origin of Species by Means of Natural Selection. This book, one of the most important books ever written, has directly impacted our civilization and sparked many new ideas and fields of science.

In the introduction to On the Origin of Species by Means of Natural Selection, Darwin had this to say, “The view that each species has been independently created—is erroneous. I am fully convinced that species are not immutable; but…are lineal descendants of some other and generally extinct species, in the same manner as the acknowledged varieties of any one species are the descendants of that species. Furthermore, I am convinced that Natural Selection has been the most important, but not the exclusive, means of modification.” Then, in the conclusion, he added, “Why, may it be asked, until recently did nearly all the most eminent living naturalists and geologists disbelieve in the mutability of species? It cannot be asserted that organic beings in a state of nature are subject to no variation; it cannot be proved that the amount of variation in the course of long ages is a limited quality; no clear distinction has been, or can be, drawn between species and well-marked varieties.” From these quotations, two of Darwin’s most profound axioms can be derived. First that species evolve through natural selection, and secondly, that species are not static in their design, but rather, can mutate. These two ideas are the staples that hold Darwin’s theory of evolution together.

This theory, the theory of evolution, has been modernized to included new discoveries made after the first printing of On the Origin of Species by Means of Natural Selection. However, those amendments were made to make the theory more complete, Darwin’s ideas are still the basis for the theory.

The theory is comprised of four major points. The first point is that variation is present within the genes of all species as the result of random mutations. The second point, commonly known as natural selection, states that in a given environment, some individuals of a species are better adapted for survival and therefore leave more offspring. The third point asserts that over time, change within a species leads to the replacement of old species by new species as less successful species become extinct. Fourthly and lastly, there is clear evidence from fossil and many other sources that the species now on Earth have descended from ancestral forms that are extinct. In a nutshell Darwin’s theory of evolution can be explained quite succinctly. Variation is the basis for all evolution; without it, species would truly be immutable. Thanks to variation, some individuals in a species are change very slightly. If these changes are bad for the individual, the individual will shortly die and not pass on the mutated gene, however, if the variation is advantageous to the individual, it is prone to better survive and have offspring that are also better prone to survive. This increased level of being prone eventually leads to a replacement of the not so prone to survive species by the individuals that are more prone. This can be seen in the fossil record of species that are now extinct.

It must be noted that Darwin did not develop all of his theories entirely by himself. While doing his field studies, Darwin read Charles Lyell’s Principles of Geology in which was detailed a theory of evolution by Jean Babtiste Lamarck. Lamarck’s theory was based on the concept of use and disuse. According to Lamarck, evolution occurs as structures develop through use, or disappear because of disuse, and that these “acquired characteristics” are passed on to offspring. Although now known to be wrong, this theory led Darwin to note how as he visited different places, there were things that could only be attributed to a process of gradual change or an evolution.

When he returned from his field studies, Darwin read an essay written by the English economist Thomas Malthus called Essay on the Principle of Population. In the essay, Malthus explained his principle of population: that the human population could cover the Earth’s entire surface within a very short period of time if it could reproduce unchecked, but would not due to death caused by disease, war, and famine.

Darwin, upon considering what Malthus had proposed, decided that Malthus’ principle of population applied to all species, not only humans. He determined that every organism had the potential to produce many offspring during its lifetime, but not all would survive. Those who would survive would do so for a reason. Here came Darwin’s most important conjecture: individuals that possess superior physical or behavioral attributes are more likely to survive than those that are not so well endowed.

The Reaction

Darwin’s contemporaries were very religious in nature. Their way of living was that of the Bible and anything opposing the facts that were written in the Bible were obviously great evils. Upon reading On the Origin of Species by Means of Natural Selection, the highly religious called Darwin a heretic, a dissident, and a schismatist. They were outraged that someone would tinker with one of the most basic truths in their religion: creation, the idea that all life was created by God and that it has not changed since he created it.

However, the enlightened few could not help but believe what Darwin had theorized; they could not ignore the evident. Ockham’s razor is a basic scientific idea that suggests that the simpler a theory is, the better. If two theories predict phenomena to the same accuracy, then the one which is simpler is the better one. Moreover, additional aspects of a theory which do not lend it more powerful predicting ability are unnecessary and should be stripped away. Those aware of Ockham’s razor would immediately believe Darwin’s view over those of the religious folk. The first theory, that an omni-powerful God created everything would seem too difficult and not easy to understand over the second theory, Darwin’s, where everything could be explained through reason and intellect rather than blind faith.

Darwin was a very wise man; he could foresee the controversy that his book would bring. To bring some of this controversy to rest, he included the this passage in the final page of On the Origin of Species by Means of Natural Selection, “…from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows. There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.

From the beginning Darwin was a creationist, and, despite the development of his theory, continued to be one. In the last passage Darwin clearly stated that God created one or a few very basic life forms and from those, all of the ones we have today evolved. He found this view more beautiful than that which he and most other people previously held (that God created everything and that it still is as he created it, without change). The idea that life has no limits and that life will continue to evolve into wonderful creations is indeed an amazing and awe-inspiring thought.


If Darwin were a person of the twentieth century and released On the Origin of Species by Means of Natural Selection in our lifetimes, it would be difficult to tell what the reaction would be. Surely, there would be some criticism from the church and from various political parties. However, from the scientific community, Darwin would receive much praise. I would not find it surprising if Darwin were to receive the Nobel Prize for his contributions to science. Then again, I do not know under what category the prize would be given, since without him, there would be no genetics! By contributing the theory of evolution to the world he has changed it in ways unimaginable.

pealco's note: I wrote this for an extra credit assignment in high school biology.

"From the beginning Darwin was a creationist, and, despite the development of his theory, continued to be one. "

I find this claim questionable. While it is true that Darwin has tried to avoid the subject of religion / creation most of the time, his later works were much more critical of religion than his earlier ones. In the introduction of The Descent of Man, Darwin wrote:

"Ignorance more frequently begets confidence than does knowledge: it is those who know little, and not those who know much, who so positively assert that this or that problem will never be solved by science." (Charles Darwin, Introduction to "The Descent of Man," 1871)

Later on in the book he dismisses an argument for religion being innate:

"Belief in God- Religion.- There is no evidence that man was aboriginally endowed with the ennobling belief in the existence of an Omnipotent God. On the contrary there is ample evidence, derived not from hasty travellers, but from men who have long resided with savages, that numerous races have existed, and still exist, who have no idea of one or more gods, and who have no words in their languages to express such an idea. The question is of course wholly distinct from that higher one, whether there exists a Creator and Ruler of the universe; and this has been answered in the affirmative by some of the highest intellects that have ever existed."

"The belief in God has often been advanced as not only the greatest, but the most complete of all the distinctions between man and the lower animals. It is however impossible, as we have seen, to maintain that this belief is innate or instinctive in man. On the other hand a belief in all-pervading spiritual agencies seems to be universal; and apparently follows from a considerable advance in man's reason, and from a still greater advance in his faculties of imagination, curiosity and wonder. I am aware that the assumed instinctive belief in God has been used by many persons as an argument for His existence. But this is a rash argument, as we should thus be compelled to believe in the existence of many cruel and malignant spirits, only a little more powerful than man; for the belief in them is far more general than in a beneficent Deity. The idea of a universal and beneficent Creator does not seem to arise in the mind of man, until he has been elevated by long-continued culture."

His attacks on religion got sharper the older he became, and his posthumously published autobiography contained quotes about Christianity that were omitted by Darwin's wife Emma and his son Francis because they were deemed dangerous for Charles Darwin's reputation. Only in 1958 Darwin's granddaughter Nora Barlow published a revised version which contained the omissions. Here are some quotes which I have taken from the webpage <http://au.atheism.org/darwin.html>:

Evolving Disbelief

"Whilst on board the Beagle (October 1836-January 1839) I was quite orthodox, and I remember being heartily laughed at by several of the officers (though themselves orthodox) for quoting the Bible as an unanswerable authority on some point of morality. I suppose it was the novelty of the argument that amused them. But I had gradually come, by this time, to see that the Old Testament; from its manifestly false history of the world, with the Tower of Babel, the rainbow as a sign, etc., etc., and from its attributing to God the feelings of a revengeful tyrant, was no more to be trusted than the sacred books of the Hindoos, or the beliefs of any barbarian." (Charles Darwin: The Autobiography of Charles Darwin with original omissions restored. New York, Norton, 1969. p.85)

"By further reflecting that the clearest evidence would be requisite to make any sane man believe in the miracles by which Christianity is supported, --that the more we know of the fixed laws of nature the more incredible, do miracles become, --that the men at that time were ignorant and credulous to a degree almost incomprehensible by us, --that the Gospels cannot be proved to have been written simultaneously with the events, --that they differ in many important details, far too important as it seemed to me to be admitted as the usual inaccuracies of eyewitness; --by such reflections as these, which I give not as having the least novelty or value, but as they influenced me, I gradually came to disbelieve in Christianity as a divine revelation. The fact that many false religions have spread over large portions of the earth like wild-fire had some weight with me. Beautiful as is the morality of the New Testament, it can hardly be denied that its perfection depends in part on the interpretation which we now put on metaphors and allegories." p86

"Thus disbelief crept over me at a very slow rate, but at last was complete. The rate was so slow that I felt no distress, and have never since doubted even for a single second that my conclusion was correct." p.87

"I can indeed hardly see how anyone ought to wish Christianity to be true; for if so the plain language of the text seems to show that the men who do not believe, and this would include my Father, Brother and almost all my best friends, will be everlastingly punished. And this is a damnable doctrine." p87

The Design Argument

"The old argument of design in nature, as given by Paley, which formerly seemed to me so conclusive, fails, now that the law of natural selection had been discovered. We can no longer argue that, for instance, the beautiful hinge of a bivalve shell must have been made by an intelligent being, like the hinge of a door by man. There seems to be no more design in the variability of organic beings and in the action of natural selection, than in the course which the wind blows. Everything in nature is the result of fixed laws." p.87

Existence Of Suffering

"That there is much suffering in the world no one disputes. Some have attempted to explain this in reference to man by imagining that it serves for his moral improvement. But the number of men in the world is as nothing compared with that of all the other sentient beings, and these other suffer greatly without any moral improvement. A being so powerful and so full of knowledge as a God who could create the universe, is to our finite minds omnipotent and omniscient, and it revolts our understanding to suppose his benevolence is not unbounded, for what advantage can there be in the sufferings of millions of the lower animals throughout almost endless time? This very old argument from the existence of suffering against the existence of an intelligent first cause seems to me a strong one; whereas, as just remarked, the presence of much suffering agrees well with the view that all organic beings have developed through variation and natural selection." (emphasis added) p.90

The Existence Of God

"At the present day (ca. 1872) the most usual argument for the existence of an intelligent God is drawn from the deep inward conviction and feelings which are experienced by moat persons. But it cannot be doubted that Hindoos, Mahomadans and others might argue in the same manner and with equal force in favor of the existence of one God, or of many Gods, or as with the Buddists of no God...This argument would be a valid one if all men of all races had the same inward conviction of the existence of one God: but we know that this is very far from being the case. Therefore I cannot see that such inward convictions and feelings are of any weight as evidence of what really exists." p.91

"Nor must we overlook the probability of the constant inculcation in a belief in God on the minds of children producing so strong and perhaps as inherited effect on their brains not yet fully developed, that it would be as difficult for them to throw off their belief in God, as for a monkey to throw off its instinctive fear and hatred of a snake." p.93

Judging by Darwin's own statements, the only reason I see for him not becoming an outspoken atheist is the religious fundamentalism of his contemporaries.

not autonoded. not prepared with text formatter. please follow the hardlinks.

On the Origin of Species by Means of Natural Selection,

or the

Preservation of Favoured Races in the Struggle for Life.

By Charles Darwin



Chapter I(A,B, C)

Variation under Domestication

Causes of Variability -- Effects of Habit -- Correlation of Growth --Inheritance -- Character of Domestic Varieties -- Difficulty ofdistinguishing between Varieties and Species -- Origin of DomesticVarieties from one or more Species -- Domestic Pigeons, their Differencesand Origin -- Principle of Selection anciently followed, its Effects --Methodical and Unconscious Selection -- Unknown Origin of our DomesticProductions -- Circumstances favourable to Man's power of Selection.

Chapter II

Variation under Nature

Variability -- Individual Differences -- Doubtful species -- Wide ranging,much diffused, and common species vary most -- Species of the larger generain any country vary more than the species of the smaller genera -- Many ofthe species of the larger genera resemble varieties in being very closely,but unequally, related to each other, and in having restricted ranges.

Chapter III(A,B)

Struggle for Existence

Bears on natural selection -- The term used in a wide sense -- Geometricalpowers of increase -- Rapid increase of naturalised animals and plants --Nature of the checks to increase -- Competition universal -- Effects ofclimate -- Protection from the number of individuals -- Complex relationsof all animals and plants throughout nature -- Struggle for life mostsevere between individuals and varieties of the same species; often severebetween species of the same genus -- The relation of organism to organismthe most important of all relations.

Chapter IV(A,B, C)

Natural Selection

Natural Selection -- its power compared with man's selection -- its poweron characters of trifling importance -- its power at all ages and on bothsexes -- Sexual Selection -- On the generality of intercrosses betweenindividuals of the same species -- Circumstances favourable andunfavourable to Natural Selection, namely, intercrossing, isolation, numberof individuals -- Slow action -- Extinction caused by Natural Selection --Divergence of Character, related to the diversity of inhabitants of anysmall area, and to naturalisation -- Action of Natural Selection, throughDivergence of Character and Extinction, on the descendants from a commonparent -- Explains the Grouping of all organic beings.

Chapter V(A,B, C)

Laws of Variation

Effects of external conditions -- Use and disuse, combined with naturalselection; organs of flight and of vision -- Acclimatisation -- Correlationof growth -- Compensation and economy of growth -- False correlations --Multiple, rudimentary, and lowly organised structures variable -- Partsdeveloped in an unusual manner are highly variable: specific charactersmore variable than generic: secondary sexual characters variable --Species of the same genus vary in an analogous manner -- Reversions tolong-lost characters -- Summary.

Chapter VI(A,B, C)

Difficulties on Theory

Difficulties on the theory of descent with modification -- Transitions --Absence or rarity of transitional varieties -- Transitions in habits oflife -- Diversified habits in the same species -- Species with habitswidely different from those of their allies -- Organs of extreme perfection-- Means of transition -- Cases of difficulty -- Natura non facit saltum --Organs of small importance -- Organs not in all cases absolutely perfect --The law of Unity of Type and of the Conditions of Existence embraced by thetheory of Natural Selection.

Chapter VII(A,B, C)


Instincts comparable with habits, but different in their origin --Instincts graduated -- Aphides and ants -- Instincts variable -- Domesticinstincts, their origin -- Natural instincts of the cuckoo, ostrich, andparasitic bees -- Slave-making ants -- Hive-bee, its cell-making instinct -- Difficulties on the theory of the Natural Selection of instincts --Neuter or sterile insects -- Summary.

Chapter VIII(A,B)


Distinction between the sterility of first crosses and of hybrids --Sterility various in degree, not universal, affected by closeinterbreeding, removed by domestication -- Laws governing the sterility ofhybrids -- Sterility not a special endowment, but incidental on otherdifferences -- Causes of the sterility of first crosses and of hybrids --Parallelism between the effects of changed conditions of life and crossing-- Fertility of varieties when crossed and of their mongrel offspring notuniversal -- Hybrids and mongrels compared independently of their fertility-- Summary.

Chapter IX(A,B)

On the Imperfection of the Geological Record

On the absence of intermediate varieties at the present day -- On thenature of extinct intermediate varieties; on their number -- On the vastlapse of time, as inferred from the rate of deposition and of denudation --On the poorness of our palaeontological collections -- On the intermittenceof geological formations -- On the absence of intermediate varieties in anyone formation -- On the sudden appearance of groups of species -- On theirsudden appearance in the lowest known fossiliferous strata.

Chapter X(A,B, C)

On the Geological Succession of Organic Beings

On the slow and successive appearance of new species -- On their differentrates of change -- Species once lost do not reappear -- Groups of speciesfollow the same general rules in their appearance and disappearance as dosingle species -- On Extinction -- On simultaneous changes in the forms oflife throughout the world -- On the affinities of extinct species to eachother and to living species -- On the state of development of ancient forms-- On the succession of the same types within the same areas -- Summary ofpreceding and present chapters.

Chapter XI(A,B, C)

Geographical Distribution

Present distribution cannot be accounted for by differences in physicalconditions -- Importance of barriers -- Affinity of the productions of thesame continent -- Centres of creation -- Means of dispersal, by changes ofclimate and of the level of the land, and by occasional means -- Dispersalduring the Glacial period co-extensive with the world.

Chapter XII(A,B)

Geographical Distribution -- continued

Distribution of fresh-water productions -- On the inhabitants of oceanicislands -- Absence of Batrachians and of terrestrial Mammals -- On therelation of the inhabitants of islands to those of the nearest mainland --On colonisation from the nearest source with subsequent modification --Summary of the last and present chapters.

Chapter XIII(A,B, C)

Mutual Affinities of Organic Beings:
Morphology: Embryology: Rudimentary Organs

Classification, groups subordinate to groups -- Natural system -- Rules anddifficulties in classification, explained on the theory of descent withmodification -- Classification of varieties -- Descent always used inclassification -- Analogical or adaptive characters -- Affinities, general,complex and radiating -- Extinction separates and defines groups --Morphology, between members of the same class, between parts of the sameindividual -- Embryology, laws of, explained by variations not superveningat an early age, and being inherited at a corresponding age -- RudimentaryOrgans; their origin explained -- Summary.

Chapter XIV(A,B)

Recapitulation and Conclusion

Recapitulation of the difficulties on the theory of Natural Selection --Recapitulation of the general and special circumstances in its favour --Causes of the general belief in the immutability of species -- How far thetheory of natural selection may be extended -- Effects of its adoption onthe study of Natural history -- Concluding remarks.


Reflections on the Origin of Species is a series of essays I wrote. Each focuses on a chapter of The Origin of Species as well as the corresponding chapter of Darwin's Ghost: The Origin of Species Updated by Steve Jones. They are noded chapter for chapter as follows:

  • Introduction (See below)
  1. "Variation Under Domestication"
  2. "Variation Under Nature"
  3. "Struggle for Existence"
  4. "Natural Selection"
  5. "Laws of Variation"
  6. "Difficulties on Theory"
  7. "Instinct"
  8. "Hybridism"
  9. "On the Imperfection of the Geological Record"
  10. "On the Geological Succession of Organic Beings"
  11. "Geographical Distribution"
  12. "Geographical Distribution—continued"
  13. "Mutual Affinities of Organic Beings; Morphology; Embryology; Rudimentary Organs"
    "Almost Like a Whale?" (about Darwin's Ghost only)
  14. "Recapitulation and Conclusion" (about The Origin of Species only)
  15. Introduction

    On the Origin of Species by Means of Natural Selection by Charles Darwin and Darwin’s Ghost by Steve Jones both attempt to explain the ideas behind Darwin’s theories of evolution and natural selection. These ideas are arguments for evolution and against Young Earth Creationists who claim that modern species were created by God within the last 6500 years. In this series of essays, I will go through the chapters of each of these books, which parallel each other, and see what arguments are made.

    I will begin at the beginning. Starting with the second edition of The Origin of Species, the book began with a chapter titled "An Historical Sketch of the Progress of Opinion on the Origin of Species, Previously to the Publication of the First Edition of This Work." It appears that this chapter is not always included in current publications of the book, which is understandable, considering that it is quite dense and consists of a series of references, comments, and quotes. In one place Darwin quotes a biologist in French without translation. Clearly he was not writing for a modern audience.

    Darwin’s Ghost also starts with a chapter called "An Historical Sketch of the Progress of Opinion on the Origin of Species," but this one is quite different. In Jones' Historical Sketch, he gives some basic explanations for Darwin’s theory. He also explains the goal of his book: it "tries to read Charles Darwin’s mind with the benefit of scientific hindsight." He expresses his opinion that evolutionary theories have become so important to science, economics, politics, history, and art that "no educated person can afford to ignore them." And he notes that, like The Origin of Species, Darwin’s Ghost is an argument. It is not meant to be a biography or textbook, and is not exhaustive in the way these types of books are.

    Following the Historical Sketch in each of these books is an introduction. In Darwin’s introduction, he apologizes for his failure to write a long book with many references. As he writes, some things "can be treated properly only by giving long catalogues of facts." Darwin did not, however, write such a book. He has two reasons for this. First, he estimated that it would take him two or three more years to finish his research, and he was not in good health. Second, in 1858 he received a letter from Alfred Russel Wallace, another naturalist, who had independently come up with a theory almost identical to Darwin’s. Because of these two factors, Darwin decided to publish The Origin of Species as an abstract to his larger book, which he never completed.

    Darwin also used his introduction to lay out a plan for the book, explaining what each chapter will cover. Even with his profuse apologies for not writing a longer, more boring book, his introduction is only five pages long. Jones, on the other hand, follows his Historical Sketch with a twenty-page introduction, which covers three main topics. The first of these, covered only briefly, is Young-Earth Creationism. On this topic Jones writes, "Such intolerance is new. At the end of the last century few clerics opposed the idea of evolution." He also writes that "most were willing to accept a compromise between The Origin and the Bible. A Day of Creation might be millions of years long, or might represent six real days that marked the origin of a spiritual Man after the long ages it took all else to evolve. Real bigotry had to wait for modern times."

    He then argues that, since Darwin, an extremely strong piece of evidence for Darwin’s theories has emerged. This evidence is his second topic, the AIDS virus. Jones describes the history and biology of HIV and AIDS, and how various forms of HIV have diverged over time. He explains that HIV now exists in two entirely separate species, HIV-1 and HIV-2. If different strains of HIV-1 come together in one person, they may combine to make a new strain. The same is true for HIV-2. However, the two forms of HIV cannot breed with each other. Although, as we will soon see in our chapter on "Variation Under Nature," there is still some controversy among biologists about how to define the word species, the main criterion for separation of species is whether or not they interbreed. Hence, HIV-1 and HIV-2 are separate species, and are a prime piece of evidence for what is sometimes called speciation, since we know that they have diverged within recent history.

    After making these points about HIV, Jones moves on. Jones’ third topic for his introduction is the evolution of the whale. The whale is an animal that critics of Darwin’s have claimed as evidence against his theory, because it appears so unrelated to other mammals. Jones traces the genealogy of the whale, describing how it evolved in the part of the world that is now India and Pakistan. At one time, this area was an ocean, the Tethys Sea. Interestingly, the closest modern land-dwelling relative of the whale is the hippopotamus.

    Throughout Jones’ introduction, he uses analogies and connections between his topics, explaining how AIDS offers us a proof of evolution and speciation, thus weakening the arguments of creationists, and how the evolution of the whale and the HIV virus parallel each other. He ends the chapter with a quote by Galileo, originally about his own theories, but equally relevant to the debate about evolution. Galileo said that it would be "a terrible detriment for the souls if people found themselves convinced by proof of something which it was made a sin to believe."

    | Variation Under Domestication >

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