Some years ago, when I was delivering a lecture at the Cathedral Hall of Westminster, in the course of the questioning which took place at the termination of the discourse, which was on vitalism, I was asked by one who signed his paper, "So and So, Atheist," "What would you say if you saw a duck come out of a hen's egg?" I recognised at once the idea at the back of the question and appreciated the fact that it had been asked by one who, as some one has said, "called himself an advanced free-thinker, but was really a very ignorant and vulgar person who was suffering from a surfeit of the ideas of certain people cleverer than himself." But, as a full discussion of the matter would have taken at least as long as the lecture which I had just concluded, my reply was that before I attempted to explain it I would wait to see the duck come out of the hen's egg, since no man had as yet witnessed such an event. I do not know whether my atheistical questioner was satisfied or not, but I heard no more of him. But, after all, is it not a marvellous thing that a duck never does come out of a hen's egg? If everything happens by chance, as some would have us believe, why is it that a duck does not occasionally emerge from a hen's egg? Surely this is a miraculum, a thing to be wondered at, yet so common that it goes unnoticed, like many other wonderful things which are also matters of common everyday occurrence, such as the spinning of the earth on its own axis and its course round the sun and through the heavens.

If we pursue this question further we shall begin to remember that creatures more nearly related to one another also "breed true." The hen and the duck are both birds, but they are not so nearly allied to one another as the lion and the tiger, both of which are FelidÆ, or cats. Yet no one ever expects that a tiger will be born of a lioness, or vice versa. Further, the pug and the greyhound are both of them dogs: the name canis domesticus applies to both, and one would be distinguished from the other in a scientific list as "Var. (i.e. variety) 'pug,'" or "Var. 'greyhound.'" Yet one can imagine the surprise of a breeder if a greyhound was born in his carefully selected and guarded kennel of pugs. In a word, not only species, but varieties do tend to breed true; the child does resemble its parent or parents. No doubt the resemblance is not absolute: there is variation as well as inheritance. Sometimes the variation may be recognised as a feature possessed by a grandparent or even by some collateral relative such as an uncle or great-uncle; sometimes this may not be the case, though the non-recognition of the likeness does not in any way preclude the possibility that the peculiarity may have been also possessed by some other member of the family. But on the whole the offspring does closely resemble its parents; that is to say, not only the species and the variety but the individual "breeds true." "Look like dey are bleedzed to take atter der pa," as Uncle Remus said when he was explaining how the rabbit comes to have a bobtail. Moreover this resemblance is not merely in the great general features. Apart from monstrosities, the children of human beings are human beings; the children of white parents have white skins, those of black progenitors are black. Commonly, though not always by any means, the children of dark-haired parents are themselves dark-haired, and so on. But smaller features are also transmitted, and transmitted too for many generations; for example, the well-known case of the Hapsburg lip, visible in so many portraits of Spanish monarchs and their near relatives, and visible in life to-day. Again, there are families in which the inner part of one eyebrow has the hairs growing upwards instead of in the ordinary way, a feature which is handed on from one generation to another. Even more minute features than this have been known to be transmissible and transmitted, such as a tiny pit in the skin on the ear or on the face. In fact, there is hardly any feature, no matter how small, which may not become a hereditary possession.

If in-and-in breeding occur, as it may do amongst human beings in a locality much removed from other places of habitation, it may even happen that what may be looked upon as a variety of the human race may arise, though when it arises it is always easy to wipe it out and restore things to the normal by the introduction of fresh blood, to use the misleading term commonly employed, where the Biblical word "seed" comes much nearer to the facts.

Thus there is a well-authenticated case in France (in Brittany if I remember right) of a six-fingered race which existed for a number of generations in a very isolated place and was restored to five-fingeredness when an increase in the populousness of the district permitted a wider selection in the matter of marriages.

And similarly, not long ago an account was published of an albino race somewhere in Canada which had acquired a special name.

Perhaps it has been wiped out by this time by wider marriages, though these might be effected with greater difficulty by albinos than by six-fingered persons. At any rate no one can doubt that it might at any time be wiped out by such marriages, though even when apparently wiped out, sporadic cases might be expected to occur: what the breeders call "throws-back," when they see an animal which resembles some ancestor further back in the line of descent than its actual progenitors. Certainly the most remarkable instance of the reliance which we have come to feel respecting this matter of inheritance is that which was afforded by a recent case of disputed paternity interesting on both sides of the Atlantic, since the events in dispute occurred in America and the property and the dispute concerning it were in England.

It was obviously a most difficult and disputable case, but the judge, a shrewd observer, noticed, when the putative father was in the box, a feature in his countenance which seemed closely to resemble what was to be seen in the child which he claimed to be his own. A careful examination of the parents and of the child was made by an eminent sculptor, accustomed to minute observation of small features of variety in those sitting to him as models.

He reported and showed to the court that there were remarkable features in the head of the child which resembled, on the one hand an unusual configuration in the mother—or the woman who claimed to be the mother—and on the other a well-marked feature in her husband. And as a result the father and mother won their case, and were proclaimed the parents of the child because of the resemblance of these features; and, if we think for a moment, we shall see, because also of the reliance which the human race has come to place in the fidelity of inheritance, of its perfect certainty, so to speak, that a duck will not come out of a hen's egg, and the fact of this reliance on a generally received truth remains, whatever may be said as to the legal aspect of such evidence.

Inheritance is a fact recognised by everybody, and the only reason why we refuse to wonder at it is because, like other wonderful yet everyday facts, such as the growth of a great tree from a tiny seed, it is so everyday that we have ceased to wonder at it. It is there: we know that. But have we any kind of idea how it comes about? The duck does not, as a matter of common experience, come out of a hen's egg. Why does it come out of a duck's egg? Why doesn't it come out, if only rarely, from a hen's egg? In other words, do we know what it is that explains inheritance or how it is that there is such a thing as inheritance? Well, candour obliges me to say that we do not. In spite of all the work which has been expended upon this question we are totally ignorant of the mechanism of heredity. Nevertheless it will be instructive to glance at the theories which have been put forward to explain this matter.

All living things spring from a small germ, and in the vast majority of cases this germ is the product in part of the male and in part of the female parent. It is therefore natural that we should in the first place turn our attention to this germ and ask ourselves whether there is anything in its construction which will give us the key of the mystery. There is not, at least there is nothing definite as shown by our most powerful microscopes. To be sure there is a remarkable substance, called chromatin because of its capacity for taking up certain dyes, which evidently plays some profoundly important part in the processes of development. We may suspect that this is the thing which carries the physical characteristics from one generation to another, but we cannot prove it; and though some authorities think that it is, others deny it. Even if it be, it can hardly be supposed that microscopic research will ever be able to establish the fact, and that for reasons which must now be explained.

Let us suppose that we visit a vast botanic garden, and in the seed-time of each of the plants therein contained select from each plant a single ripe seed. It is clear that, if we take home that collection of seeds, we shall have in them a miniature picture of the garden from which they were culled, or at least we shall be in possession of the potentiality of such a garden, for, if we sow these seeds and have the good fortune to see them all develop, take root and grow, we shall actually possess a replica of the garden from which they came. Not exactly, it may be urged, for the distribution or arrangement of the seeds must have been carefully looked to, if the gardens are to resemble each other otherwise than in the mere possession of identical plants. I admit the truth of this, but cannot for the moment discuss it. At any rate we should have the same plants in both gardens.

On this analogy, many have suggested that every organ in the body—we must go further, and say that every marked feature in every organ in the body—is represented in the germ by a seed which can grow, under favourable circumstances, into just such another organ or feature of an organ. This was the theory put forward by Darwin under the name of "pangenesis," and by others under other titles with which it is unnecessary to burden these pages. All these theories have been summed together under the name "micromeristic," that is small-fragmented, or again, "particulate," since they all postulate the existence in the germ of innumerable small fragments—seeds—which are capable of growing into complete plants or organs under favourable circumstances. Again, this, even if true, does not by any means exhaust the matter, for it does not explain why the seed of the eye implants itself and grows in the right place in the head instead of making a home for itself, let us say, in the sole of the foot. But again we must pass over that matter.

There is nothing inherently impossible in this theory; indeed, if we allow that the transmission of inheritable characteristics is purely material, and it may be, there is only one other conceivable way in which it can occur. It is true that the seeds must be almost innumerable, but the germ, though small, is capable of accommodating an almost innumerable number of independent factors, if the prevalent views as to the constitution of matter are to be believed. And, as it is quite inconceivable that we can ever have microscopes which could detect such minute objects as the ultimate bricks of which the atom—no, not even the atoms themselves which compose the germ—consists, it is impossible that we should be able to say that the seed-theory is untrue. Even if we could see these ultimate constituents it is in the last degree unlikely that they would have any resemblance to the things which are, on this theory to grow from them, any more than the acorn resembles the oak which is to spring from it.

But observe! the germ on this view must contain not only seeds from the immediate parents but from many, perhaps all, of the older generations of the family, otherwise how are we to account for the appearance of ancestral peculiarities which the father and mother do not show? Moreover, since very minute things, like the inner angle of the eyebrow, may independently vary, there must be an enormous number of seeds apart altogether from the considerations alluded to in the last paragraph. And many authorities who have closely considered the question have come to the conclusion that the complexities introduced would be so great that it is impossible to believe in any micromeristic theory.

Then, of course, we must look out for some other explanation, and some have suggested that it is to be found in memory—the memory of the germ of what it was once part and the anticipation of what it may once more be. This again is an explanation not susceptible of proof along the lines of a chemical experiment, but not necessarily, therefore, untrue. Of course there are two ideas as to memory. If we are pure materialists and imagine every memory in our possession as something stamped, in some wholly incomprehensible manner, on some cell of our brain and looked at there, by some wholly inconceivable agency, when we sit down to think of past days, then we must look on the germ, under the "mnemic" or memory theory as consisting of fragments each of them impressed with the "memory" of some particular organ or feature of the body, and lo! we find ourselves back again in micromerism. If we are to take a non-materialistic view of memory we are plunged into a metaphysical discussion which cannot here be pursued. A third explanation, which by the way explains nothing, is that the whole matter is one of "arrangement," to which we shall return at the close of this paper.

The mechanism of inheritance must either be physical[33] or it must be non-physical; that is, immaterial. This is what emerges from our discussion, and so far as science goes to-day it must be admitted that neither of these explanations can be said to be accepted generally by men of science or proved—perhaps even capable of proof—by scientific methods. If we know little or nothing about the mechanism of inheritance, can we and do we know anything about the laws under which it works, or has it any laws? Or are its operations a mere chance-medley? It is hardly necessary to ask the latter question, for chance-medley could not lead to regular operations—operations so regular that a court of law may act upon their evidence. Yes: we answer to the first question very lightly but without perhaps always thinking what that affirmative answer implies, a point to be considered in a moment. It may at once be said that we do now know a good deal about the laws under which inheritance works itself out, and that knowledge, as most people are now aware, is due to the quiet and for a time forgotten labours of Johann Gregor Mendel, once Abbot of the Augustinian Abbey of BrÜnn, a prelate of that Church which loud-voiced ignoramuses are never tired of proclaiming to have been from the beginning even down to the present day the impassioned and deadly enemy of all scientific progress. Mendel saw that former workers at inheritance had been directing their attention to the tout ensemble of an individual or natural object; his idea was analytical in its nature, for he directed his attention to individual characteristics, such as stature or colour, or the like. And having thus directed his attention and confined his labours mainly to plants, since the study of generations of most animals is too lengthy a process for one man to carry out, he did in fact discover that there are very definite laws, capable even of numerical statement, under which inheritance acts. There is no need to explain or discuss them here: suffice it to say that there are such laws,[34] as is now admitted by an overwhelming majority of the biologists of to-day. Mendel's facts were hidden in a somewhat obscure journal; they lay dormant, much to his annoyance, during his lifetime. Years after his death his papers were unearthed, and his discoveries have been proclaimed as being as fundamental to biology as those of Newton and Dalton to other sciences.

There are, then, laws. That means one of two things: either that these laws arose by chance-medley, or that some one enacted them. It seems impossible, when one surveys the orderly operations of Nature, among which are those conducted under the laws known by the name of their discoverer, Mendel—it seems wholly impossible that these operations arose by chance-medley. To me, at any rate, any such explanation is wholly unthinkable. But if it be an impossible explanation, as I and many thousands, not to say millions, of other persons believe, then there is no other way out of it than that these operations must have been planned by some one; in other words, that there must have been a Creator and Deviser of the world.

People hide from this explanation, and one of the favourite sandbanks in which this particular kind of human ostrich plunges its head is "Nature." "Nature does this," and "Nature does that," forgetting entirely the fact that "Nature" is a mere personification and means either chance-medley or a Creator, according to the old dilemma. There is a very curious example of this inability or unwillingness to admit—perhaps even to understand—the force of this argument exhibited by those to whom one would suppose that it would come home with overpowering force: I mean, of course, the Mendelians.

The most learned of these, and one of the most open-minded of men, hints in one place that though he does not think it necessary himself to believe it, yet it might at least be suggested that, if in a certain organism we find things so placed that a certain combination is bound to emerge in a certain generation, such a state of affairs might have been prearranged. Now, if it was prearranged, the awful fact emerges that there must have been an arranger; in other words, a creative power. This explanation is taboo in certain circles. But one may reasonably ask, "What then?" Is it really suggested that these orderly sets of occurrences may occur not once or twice only but thousands and thousands of times, and this may all happen by chance? A very distant acquaintance with the mathematics of probability will show that this is a wholly untenable theory. We are generally answered by some purely verbal explanation, like the personification of "Nature" already alluded to.

Thus, in a recent discussion on inheritance in a Presidential Address to the British Association, to which I have already alluded, the writer with whose explanation I have just been dealing states that he thinks it "unlikely" that the factors of inheritance are "in any simple or literal sense material particles," and proceeds thus: "I suspect rather that their properties depend on some phenomenon of arrangement." Now, in the first place, this is no explanation at all, for the mechanism of inheritance must be either material or immaterial. If there is a phenomenon of "arrangement" there must be something to be "arranged," and this something can hardly be other than material if it is to be "arranged" at all. But let that pass. What is far more important is to remember that if a thing is to be "arranged" there must be somebody to "arrange" it, for chance-medley cannot "arrange" anything in an orderly manner; or if it could do so once, cannot be supposed capable of doing it a second time in a precisely similar manner, not to say capable of doing it countless thousands of times.

If we go into a great museum our first idea, perhaps our last, concerns the arrangement found therein. But it may safely be said that no sane person ever entertained that idea without being perfectly aware that the arrangement was made by human hands, controlled, in the last resort, by the brain of the curator of the museum. Now, in a sense, the living body is a museum containing specimens of different kinds of cells. There are brain-cells, liver-cells, bone-cells, scores of different varieties of cells, and all of them, so to speak, are arranged in their appropriate cases.

If we go to the brain-case we can search it through and through without finding a liver-cell, any more than we should find a typical brain-cell embedded in the marrow of one of the bones. The different specimens all occupy their appropriate positions. How did they get there? The future animal, like animals of all kinds, including man, commences as a single cell. All save a few interesting but at present negligible cases are composed of elements drawn from male and female parents. This cell divides up into a multitude of others. At first these are to all appearances identical, but later they begin to differentiate, at first into three classes and afterwards into the multitude of different cells of which the body is composed. Further, these groups of cells become aggregated in appropriate groups, cells of one kind uniting with cells of the same kind and with no others. Here we have to do with arrangement, consummately skilful arrangement, an arrangement which practically never fails, for, leaving aside the case of monstrosity, a consideration of which would detain us too long, not merely are the various cells all placed in their proper positions, as we have seen, but their aggregation, the individual, is so formed as to belong to the proper compartment of that large museum, the world—the same compartment as that occupied by his progenitors. Neither the particulate nor the chemical theories help us here. The mnemic would, but it has its initial and insuperable difficulty, pointed out in another article in this volume, that, as you must have an experience before you can remember it, it in no way accounts for the first operation of arrangement. As to the material explanations, particulate or chemical, they amount to something like this: you have half a cart-load of bricks from one yard and half a cart-load from another, and when the bricks are dumped down in an appropriate place they form a little house, just like those occupied by the managers of the brickyards. So they may, but no one in his sense supposes that they will thus arrange themselves of their own power. Some one must arrange them. Who arranges the tiny bricks of which the animal body consists, or what arranges them? To revert to our previous example of the garden; suppose that we bring back from that which we desire to copy a bag of seeds representing all the plants which it contains. We have a plot of land of the same size as our example; we dig it and we dung it and then we scatter our seeds perfectly haphazard over its surface. What are the odds as to their coming up in an exactly similar pattern to those in the other garden. Mathematicians, I suppose, could calculate the probabilities, but they must be infinitesimally small. Yet in the case of the animal the pattern is always observed.

It is quite useless for any one, however eminent an authority he may be, to dismiss the matter by saying "It is a phenomenon of arrangement," for that begs the whole question. A Martian visitor taken to Westminster Abbey and told that its construction was a "phenomenon of arrangement" might be expected to turn a scornful eye upon his cicerone and reply, "Any fool can see that, but who arranged it?"

Hence, though wild horses would not drag such an admission from many, we are irresistibly compelled to adopt the theory of a Creator and a Maintainer also of nature and its operations—so-called—if we are to escape from the absurdities involved in any other explanation. Thus there are very important and fundamental matters to be deduced from the very little which we know about inheritance, just as there are from a hundred and one other lines of consideration related to this world and its contents. We do not know very much—it may fairly be said we know nothing as to the vehicle of inheritance. We know a little, but it is still a very little even in comparison with what we may yet come to know as the result of careful and long-continued experiment, about the laws of inheritance. What we do learn from our knowledge, such as it is, is the fact that we can give no intelligent or intelligible explanation of the facts brought before us except on the hypothesis of a Creator and Maintainer of all things.

FOOTNOTES:

[33] A third explanation, that the mechanism of inheritance is of a chemical character, is now being put forward, and some mention of this view, which is by no means one of general acceptance, will be found in another article in this volume.