Darwin made easy

Chapter I.— GENERAL INTRODUCTION

The three chapters that follow this one are a sequel to the four already published under the title “ The Darwinian Theory.” In discussing the meaning of that theory, the difficulties that encounter its students, the evidence on which it rests and the history of the hypothesis of Darwin, the attempt was made to give in language at once popular and accurate some idea of the scientific belief of to-day as to the origin of the many species of plants and animals that lived in the past or are living now.

As the greater includes the less, the Darwinian hypothesia of the origin of species covers the particular case of the origin of man. But man has only quite of late learned to regard himself as amenable to the same general laws, no more and no less, as the rest of Nature. Hence, even when the first outburst of ignorance against the principles taught by Darwin had in part died away, there were many who, whilst accepting with a tardy grace and with something of reserve those principles as affecting plants and the lower animals, regarded them as having no bearing on the question of the origin of the human race. Darwinism was all very well in respect to the lower forms of living things, but as regarded Man (with a very large M) — Oh, no !

The great naturalist, no more afraid of the conclusions to which liis generalisations led than in love with them, applied the principle of Natural Selection and that of Sexual Selection to man. Sexual Selection, briefly, works thus. In the animal kingdom males predominate in number over the females

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of particular species. The females have the opportunity of selecting certain favored males, to the exclusion of others. Hence there is a struggle among the males for the possession of the females. The arbiter is often brute force. Very often the decision of the female is determined by other considerations. More beautiful coloring or sweeter song or more artistic skill, e.g., may render certain males more acceptable than others less gifted and less happy. The sexual selection of the males that vary in some special direction as to hue, shape, voice-ability or even bodily strength results in these males having offspring, by whom the variation that has led to the selection of their lathers will be inherited, in whom it may be intensified and, in their after generations, fixed.

I have no intention in the following chapters of applying in detail the principles of Natural and Sexual Selection to man. Their application by our master led to the conclusion upon his part that man had evolved from the lower animals. My purpose is rather to give some of the evidence, direct and indifect, that points in this direction.

Of the magnitude of the question as to whence man has come there is no need to speak. That solved, the questions what man is to-day and whither he moves become possible of solution. Until we are quite clear as to the origin of man, we cannot hope to deal satisfactorily with his present conditions, or to anticipate at all definitely his destiny.

To the question, “ Whence comes man ?” only two answers are forthcoming. We have to choose between the reply of religion and of the Bible, and the reply of science and of Darwin. Either man is a special creation, and that in the image of God (Gen. i., 27), or he is the result of evolution or development from some lower form. Between these two alternatives there is no mean, and there is no peace. One is true, the other false.

A question of this kind can only be solved by an appeal to evidence, and the best judges of that evidence are scientific men. One word as to the judges ere we turn to the evidence that is to be laid before them. Every man and woman of common sense has the right to an opinion, ao^ S the expression of it. ^ But the expression is only worthy of respect at the hands of others inasmuch as it is that of an individual, unless it comes from one who, by his scientific knowledge, gives that which he says a generic value. The only claaa

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tnax can speak in any sense ex cathedra on this question is the class of men and women to whom biological questions are familiar. Nevertheless we have the clergy, with their usual presumption, not only giving, but declaiming their opinions on the scientific question of man’s origin. Once more let it be repeated that the clergyman as a clergyman has no voice in this matter whatever. You might as well ask a smuggler his opinion on the Excise Acts.

For the evidence bearing on the question in discussion. It must be either direct or indirect. On this point the reader is referred to pp. 22, 23 of the “Darwinian Theory.” All that is there said in respect to the want of all evidence, direct or indirect, for the creation of species holds in respect to the special creation of man in the image of god. Of this there is literally no evidence whatever. On the other hand, just as there is an immense, an increasing, a conclusive body of evidence, mainlv indirect, in favor of the evolution of species, a like body of evidence exists in favor of the evolution of man.

Some of this evidence is now to be given. In weighing it let us keep in mind two things : (1) that on the opposite side no evidence at all is forthcoming ; (2) that we are studying man as a whole, not merely the highest kinds of men.

In all this inquiry we have to take into account not the highest and most civilised races only, but the lowest and most degraded. It is by constantly considering only the European peoples and the contrast between them and the anthropoid or manlike apes that thoughtless people arrive at the astounding conclusion that man is infinitely superior to the lower animals. To this false conclusion the false statements of religion and of the priests have also conduced. The fact is that if we study all races of man, in no single point of his anatomy, his physiology, or his psychology is man clearly marked off from the brute. Including as human all from the loftiest men and women down to the savages, to the idiots, and to those ape men and women who, the children of normal human beings are themselves no more, and in many cases much less than apes, it may be asserted, without fear of contradiction that in every point of structure and function there is a greater difference between man and man than between man and ape — i.e., the interval between the highest man and

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the lowest man in regard to any anatomical or physiological point is greater than it is between the lowest man and the Highest ape.

The evidence to be given will be arranged under three keads. Anatomical facts, or those having to do with the structure of organs ; physiological facts, or those having to do with the function of organs ; then psychological facts, or (using the word psychology in its widest sense) those having to do with mental phaenomena. These divisions are like all the rest, artificial but useful. Especially is this artificiality noticeable in the marking off the brain functions from the rest of the body functions, and the making a distinction between psychology and the rest of physiology. The facts now to be noted are taken largely from Darwin’s “ Descent of Man.” But other authors have been laid under contribution. I ought especially to mention Dr. W. Lauder Lindsay, whose work on “ Mind in the Lower Animals,” and essays on diseases in the animal kingdom, terribly wordy as they are, contain many most useful facts.

Chapter II.— ANATOMICAL FACTS

Anatomy is derived from ava (ana) = up, to/at) (tome) = a cutting. It is the account of the structure of the body. Out of all the innumerable facts that might be given in this connexion, all pointing to man’s relationship, not only to the animals nearest to him in the scale of being, but to his relationship to others far below, some will be taken that bear on the following subjects. The hair covering of the body, the skeleton, the teeth, the blood, the brain, the ear, the eye, the muscles, the voice, the reproductive organs. In all cases let us bear in mind that the question is whether man has been created in the image of god, or whether he has risen by variation, and natural and sexual selection from some lower form of animal.

1. The hair covering. — A common objection is that the mammals below man have a covering of fur or hair that invests their bodies generally, whilst man has only the hair covering on certain parts of his body. To this objection there are many answers.

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(a) We have hairs nearly all over onr body. It is true that they are rudimentary. But they are present. Hold the hand up so that the light shines across the back of it, and the minute hairs are visible. Everywhere with the exception of the back of the extreme joints of the digits these rudimentary structures are to be seen. This is meaningless if we are made in god’s own image, as we have no evidence as to the distribution of hair on the body of deity. But if we have risen from a lower form of animal these hairs are rudiments of the coating that in our progenitors invested the body completely. [See p. 30 ‘‘Darwinian Theory.”]

(i b ) In many cases the amount of hair on the body is in proportion to the animal nature of the individual. Of course this ratio cannot be said to be invariable, as certain low savage races are without hair on the body. But in most of the civilised peoples the more hairy the skin is, the lower is the type of man. The huge powerful “ navvy,” whose muscular system is strongly developed, and in whom the intellectual faculties are not highly developed, has shaggy arms, legs, and chest.

(c) Physiologists tell us that the human embryo or foetus before birth is covered with a soft down called the lanugo (woolliness) that disappears after a time. This temporary covering of hair-like material is intelligible on the hypothesis of the evolution of man from a hair-covered animal.

( d) The cases of ape-men, or microcephali. These are, as I have already said, children of normal human parents, that revert to the simian type. These monsters, with their receding foreheads, their difficulty in walking, or inability to walk, upright, their habit of swinging from piece to piece of furniture, their ape-like grimaces, are covered as to their bodies either completely, or to a great extent, with hair.

2. The skeleton. — Just as the exoskeleton (outer protective organs) or hair covering of man does not differ essentially from that of his allies, so the endoskeleton (inner protective and supporting organs of man) differs in no essential from that of his allies. Every bone, every prominence on every bone, every marking for the attachment of muscles is the same in man as in the anthropoid apes. Of course there is not much difficulty, even to the non-anatomical mind, in distinguishing the skeleton of a European from that of a gorilla. But the

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difference in little details between the two would certainly not be so great as the difference between the skeletons of a European and an Andaman Islander. A somewhat apocryphal, but suggestive, story was wont to be told at Cambridge, which, so far as I know, has never seen the fierce light that beats on a published book. Two undergraduates visiting the anatomical museum came to the skeleton of a man and of a gorilla placed side by side for the purposes of student comparison. One of the students was an anti-Darwinian, and rather short sighted. He glided off into a sweet flow of running words upon the absurdity, not to say impropriety of dreaming for a moment that “ this, the man, could have come from that, the gorilla.” He dilated upon the enormous superiority of this to that. From these simple premisses he arrived at the conclusion that Darwin was either a fool or a rogue. Thus, for some few minutes. Then his companla., tailed his attention to the fact that the labels had been changed, and he was praising the gorilla.

To understand the thoroughness of the similarity between ■naan’s skeleton and that of his allies is only possible to a skilled anatomist. To the ordinary reader the details would be as uninteresting as unintelligible. Yet a few special facts may be given that will be understood by everyone. Let us take the cases of the tail, the hyoid bone and the visceral arches.

(a) The tail. — The objection as to the tail is nearly at an end. But there are still some ignorant people who think that they have disproved Evolution by asking how is it that man has no tail. In the first place man’s nearest neighbors, the anthropoid apes, the gorilla, the chimpanzee, the ourangoutang, the gibbon, have no tail ; or, more accurately, they have such an appendage exactly as man has. For, in the second place, man has a tail. Truly it is rudimentary. At the lower end of the vertebral column is the coccyx or os coccygis — kokkv£ (kokkux) = a cuckoo’s bill. Os = a bone. This coccyx, or os coccygis, is the remnant of the caudal appendage (canda = a tail), of the tailed animals. It is a small bone made up of three or four reduced vertebrae of no anatomical value at all. Ho muscles are inserted into the coccyx. Its value is genealogical. It tells us that the common ancestry of man and the man-like apes, was a tailed mammal.

fb) The hyoid bone. — This is a bone found in the neck of

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r the human being. It is not connected with any other bon* directly. Muscles pass from it to the bones of the head and of the chest, and the tongue is attached to it. The hyoid takes its name from a letter of the Greek alphabet (the hupsilon or u) and from eidos (eidos) = likeness. The bone has a central solid body, with two pairs of projecting horns. The horns are the greater and lesser cornua. Cornu = a horn. You can feel the larger pair of horns projecting right and left vithin the throat if you grasp your throat rather far back with the finger and thumb, so that the two digits are beneath and below the two angles of the lower jaw. That your finger and thumb are pressing the hyoid bone may be known by moving the tongue. The bony points will be found to slip away from your grasp. This little bone is the remnant of the gill-supporting apparatus of the fish. Here we have one of the cases in which bone structure in man carries us back millions on millions of years and reminds us of descent from animals that now seem too remote and too lowly to be recognised as part of the family to which he belongs in the ages. The gills of the fish are supported on a series of bony arches called branchial arches. These are in pairs. No comparative anatomist has the least doubt that the hyoid bone, with its two pairs of cornua, is the homologue (i.e., representative in structure), of two of those pairs of branchial arches. This leads me to my third point in this connexion.

( c ) The visceral arches. — Let us try to carry our minds back to the early hours of the life of the human embryo — to that strange time before its birth. Early in that life-history which begins within the organism of the mother-parent the embryo body has the front region of the side of the body quite closed, as indeed it is in the adult, whose neck of course presents no openings or clefts. But at a certain period in the embryonic life this anterior region of the lateral wall of the body shows on each side of the body certain vertical thickenings or ridges. These become more and more marked, and the integument between then thins gradually away. At last the ridges are arches, and the thin regions between them are clefts. If I may use the rough comparison, the front parts of the side of the body have the appearance of a gridiron, the bars of which are the thick arches. These arches are the visceral or branchial arches. Viscera are internal organs \iol (branchia) = gills. The clefts between them leading s

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into the interior of the human being’s body are the visceral or branchial clefts.

In this stage of development the embryo of man is therefore, as far as this region of his body is concerned, identical in structure with that of a fish. The visceral arches are the same as those that support in the fish the gills of the fish. These arches become in one or two cases part of the adult skeleton ; in others they never enter into that skeleton. Thu* the first visceral arch becomes on each side half of the lower jaw, and at the end of it, nearer to the skull, forms one of the bones of the inner ear. The second and third visceral arches make up the cornua and body of the hyoid bone. The rest become obliterated as arch-structures. As to the clefts, through which in the fish passes water that has been taken into the mouth for breathing purposes, they are in man all closed up completely at a comparatively early time. It is impossille to avoid the conclusion that this remarkable series of arches and the intervening clefts represent in their transitory appearance in the human animal the more permanent condition in a piscine ancestor of man.

3. The teeth. — The whole of the history of the teeth of the Primates (the mammalian order to which man, the anthropoid apes, the baboons, the spider monkey, the lemurs, etc., belong) is so much evidence in favor of the origin of man from some lower form. We can only take the case of the wisdom teeth. These are the four last teeth in position and in date of appearance. They are at the back of the upper and lower jaws on each side. As to their time of appearance, they may appear between the age of seventeen and that of twenty-five, or they may not appear at all. Coming comparatively late in life they generally, like Charles Lamb, make up for this by leaving early. They are really useless, placed so far back in the mouth, and very soon become lost in certain cases. In many people they are either not all four cut, or even not one of them appears. Thus the present writer has only cut 1-5 of his wisdom teeth, and he is assured by dentist friends that it is not an unusual thing for none of the four wisdom teeth to emerge. What is the significance of these wisdom teeth ? If man is made in the image of god, are we to believe that — does not the whole wickedness and absurdity of the doctrine come out at the supposition ? But if we look at the shape of the jaws of man and of the Simian Primates

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■we cfdi understand what has happened. The lower jaw of man has an angle that is nearly right — i.e., the ascending posterior portion is nearly vertical, and the lower part that runs forward runs nearly horizontally. In the lower jaw of the ape that angle is an obtuse angle — i.e., the ascending part slants somewhat backwards. With such an obtuse angled lower jaw there would be room for the last or wisdom teeth to act and work on the food. But as with advancing development the shape of the jaw altered, and the obtuse became a right angle, the wisdom teeth would be pressed upon, and would have less and less possibility of grinding the food. From disuse they are dying out. On the special creation hypothesis the wisdom teeth are a gross blunder on the part of the almighty. On the hypothesis of Evolution they are disappearing organs that were once of use to our ancestors, and their very disappearance is an argument in favor of the scientific creed.

4. The blood. — Anatomically the blood of man is not distinct from that of the higher Mammalia. Everyone is familiar with the customary reply of the medical witness in courts of justice when murder cases are the centre of interest. “Are these marks those of blood?” — “Yes.” “ Of the blood of a mammal ?” — “Yes.” “Of the blood of a human being?” — “I cannot tell.” Few facts are more important witnesses as to the community of our origin with that of the “lower” animals than this impossibility of distinguishing between our blood and theirs. By anatomical, microscopical, chemical, or physiological investigation it ia not within our power to say more than that the blood under study is fhat of some animal other than of the mammal tribe, other than the musk deer, other than one or two special animals, the shape or size of whose blood corpuscles betray them at once. The murderer who says that the stains found on his or her garments are those of a bird or of a reptile lays himself open to conviction. But whoever says it is due to a rabbit, or a dog, or any ordinary mammal, can, as far as forensic medicine is concerned, be safe. This is one of the dangers that lead to the opposition of our highly-cultivated upper classes to the further advance of education among their inferiors. Whether this educational alarm will be well or ill-founded, the fact remains that no amount of microscopic or spectroscopic investigation reveals any real

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difference between our blood and that of the majority of Mammalia.

5. The brain. — This is the organ around which the battle of ignorance and prejudice against knowledge has raged most furiously. Other organs in man may be similar to those met with in the rest of the animal kingdom. But this organ of reason and of imagination, of the poetry of a Shakespere, and the power of generalisation of a Newton must be in the human race widely separated from the organs in the non* human animals that are dignified with the same name. Precisely the same blunder that is made in comparing man generally with other animals is met with in an intensified form when the comparison is between the human brain and that of other animals. Thus the popular idea is that the brain of man in structure, volume and weight is separated from that of his fellows as by an impassable gulf. The idea is false. But it must be admitted with the deepest regret that this false idea has been originated and fostered not only by the clergy, who are not expected to know or to do better, but even by the scientific men. Again and again it is stated in works supposed to be scientific that this great gulf is fixed between our brains and those of other Mammalia. It is therefore necessary to give my authorities for the direct contradiction that I am obliged to give to this statement.

(a) As to brain structure. — There is not a single convolution or depression in the brain of man that is peculiar to him. Even the convolution to which Gratiolet clung as distinctive, the supra-marginal has been found in the orang-outang, has been found to be absent in man. On this point see Bastian, “ Brain as an Organ of Mind.”

( b ) As to brain volume. — The volume of the human brain has been found to be as much as 1,900 cubic centimetres (a. c. c. is about ^ of a cubic inch). It has been found to be as low as 1,200 c. c. in ordinary adult Europeans. Now the cubical capacity of the highest anthropoid apes may be taken as 600 c. c. Here then is a difference, 1,900 — 12,00 = 700 between man and man, and a difference 1,200 — 600 = 600 only between man and ape. More than this. If we note the volume of the brains of some of the ape-men we find that they have a cranial capacity far less than that of the ordinary anthropoid ape. Thus we know of at least ten case* of beings born of human parents in

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whom the brain volume was less than the 600 c. c. of the apes.

Name. Age. Brain Capacity.

1. Gottfried Msehre ... ... 44 555

4. Conrad Shuttelndreyer ... 31 370

5. Microcephalus of Jena ... 26 350

7. Margueiite Msehler ... 33 296

9. Jacques Moegle 10 272

10. Jean Georges Moegle ... 5 480

(c) As to brain weight. — This is, in one way, a better test than volume, just as the amount of matter in a book or a lecture or a life is of more importance than the length of either book, lecture, or life. We may take the average weight of the brain in a European man as 49 ounces. That of an anthropoid ape is 15 ounces. A great interval truly between 49 and 15. But every one of the numbers between these is to be found in the list of human brain weights. Human 'v eings have been encountered the weights of whose brain have been 48, 47, 46 ounces, and so on down to 17, 16, 15, -and beycnd. It is here only necessary to give two or three cases of weights less than the average in anthropoid apes. Professor Owen records a case of a microcephalous idiot, aged 22, in whom the brain weight was only 13T2. Professor Theile one aged 26, brain weight 10*6. Professor Marshall one aged 12, brain weight 8*5. With respect to this last case we must bear in mind that the brain weight of the child of 12 is -f- that of the adult. Thus the average European child’s brain weight would be -f- of 49 = 42 ounces. Once more then we find that the difference between the brain weights of man and man, 49 and 8*5, is greater than that between the brain weight of man and anthropoid apes, 49 and 15. For the verification of these numbers the student may be referred to Bastian’s “ Brain as an Organ of Man,” pp. 365. ....

6. The ear. — The ear is one of the most variable of the organs of the human body. This is pointed out by Professor Haeckel in his lecture on the development of the sense-organs <*“ Pedigree of Man,” Lecture X.), and. will be corroborated by

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anyone who observes the ears of any considerable collection ol people, say at a theatre or a church. In some places, at all events, more instruction may be gained from the study of the ears of our companions than of the matter for the discussion of which the assembly is convened. It is not merely that they vayy in length. Every detail of shape is variable. And this is, in the main, due to the fact that the sense of hearing is in man undergoing evolution. Perhaps no other function of our body is at the present time advancing so unmistakably as that of hearing. The various schools of music are only one proof of this growing extension of the auditory faculty.

One particular point literally is of interest to us. On the outmost edge of our ear is a littlfe prominence, of very variable size in different human beings. It is from a quarter to halfway down on the irregularly curved line that runs from the topmost part of the ear to the lobe at the bottom of the ear. This minute point is without a doubt the remnant of the point of the ear of the lower animals. There is in the order Primates amongst its various species and individuals every gradation between the acutely-pointed ears of some of the lower monkeys and the ear of man.

7. The eye. — Of all the many structures in this complex organ we can, as with the ear, only call attention to one. In the inner comer of our eye, is a small red fold dignified with the disproportionate name of the caruncula lachrymalis. A caruncle or wattle is one *of the red folds that occur on the head of the cock. The adjective lachrymalis is given because through two minute apertures in this caruncle the tears (lachrymce) pass down into the nose cavity. The caruncle is not of so much interest to us physiologically as genealogically. It is the rudiment of the third eye-lid that at present is well developed in birds and other Vertebrata. If the eyes of a bird are carefully watched the observer sees a kind of transverse or side-way winking. This is due to the drawing across the eye of the memhrana nictitans, or winking membrane, and this memhrana nictitans is the third eyelid. Here again a complete series of gradations from the perfect eyelid of the owl, e.g., to the caruncula lachrymalis of man is yielded by the study of comparative anatomy.