If any person devoted his time to the correction of popular errors, there is no probability that he would have any spare moments for eating or sleeping. The serious aspect of the present condition of popular knowledge, however, is the apparent absence of desire upon the part of many young people to grasp the principles of natural science. I am not exaggerating when I say that there are plenty of fairly educated persons in every large city who deny that man is an animal, and who insist that a whale must be a fish, because it lives in the sea.

Everybody professes to be aware in a sort of unconscious way that the theory of Evolution was invented by Mr. Darwin, and patented by Mr. Spencer, the most important points in the doctrine being that all men are descended from monkeys which had lost their tails, that the fittest survived, and that there is a “missing link” between man and his ancestors.

These ideas have little foundation in fact. Darwin no more discovered Evolution than Edison discovered electricity; we are not descended from any existing ape, with or without a tail, and no competent person ever asserted that we were; and there are good reasons for saying that such palaeontological “links” as are missing are not of the greatest possible importance. In short, whatever is evolutionary in the popular mind, is a burlesque upon the evolutionist’s true opinions.

Charles Darwin was born in 1809, on the same day as Lincoln, but, long before Darwin’s time, evolution had become a recognized force in science. Kant, who lived from 1724 to 1804, and Laplace (1749-1827) had worked out the development of the sun and the planets from white-hot gas. Lyell (1797-1875) had worked out the evolution of the earth’s surface to its present condition; and Lamarck (1744-1829) had shown that there is evidence of the descent of all animals, as well as all plants, from a few ancestors by gradual modification. Again, Herbert Spencer, during Darwin’s lifetime, began to work out the growth of mind from the most simple beginnings to the highest development of human thought.

The philosophies of the ancients were all of them founded upon limited observation; they were merely speculative fancy-pictures evolved from the author’s own consciousness. Modern science, however, is of quite a different character. It has relegated certain fundamental propositions to a region called “the Unknowable” (this means at present unknowable), and it permits everybody to explain these propositions by means of any hypotheses which may occur to him. In other words, modern science does not deal with such phenomena as are at the present day outside the range of the human intellect; and I venture to warn the reader that speculation concerning matters upon which we have as yet no scientific data is waste of time. Modern science is founded upon investigation and observation, and the evidence is always weighed as carefully and as impartially as are the statements of witnesses in a law court.

One naturally asks: “What is Evolution?” “Continuous change according to certain fixed laws,” is a reply which may have some value, although it is quite insufficient. A technical definition, given by Mr. Spencer, is as follows:

“An integration of matter and concomitant dissipation of motion, during which the matter passes from an indefinite, incoherent heterogeneity, to a definite, coherent homogeneity, and during which the retained motion undergoes a parallel transformation.” Anybody who will think about this definition will be able to appreciate its meaning, provided a good dictionary is at hand.

Evolution is not another word for Development, and Mr. Spencer has carefully distinguished the one from the other; but the details are too technical for notice in this paper. Evolution may be regarded as “a general term for the history of the steps by which any living being has acquired the morphological and physiological characters which distinguish it.” Development is “the process of differentiation by which the primitively similar parts of a living body become more and more unlike one another.” Both definitions are Huxley’s.

The evolution of organic matter now claims attention in detail. Of the origin of first life, we know absolutely nothing. The doctrine of Evolution does not deal with that. There are, however, many hypotheses upon the subject. Lord Kelvin, the eminent physicist, has suggested that unicellular life may have been transferred to this globe from a wrecked planet. This hypothesis obviously aids us very little, for it merely transfers the original scene of action to some other world. Personally, I prefer the idea that the first protoplasm was produced by the action of the sun upon inorganic matter not unlike the colloids, and that it “fed upon the previous steps in its own evolution.” In this connection, I may say that two points are certain—viz., that vegetable life preceded animal life, and that the first forms of life were mere specks of jelly, without organs. Can these primitive specks be created at the present time? Or, in other words, can protoplasm be manufactured by artificial processes? The answer must be No; not by any process now known, although a great number of experiments have been made with the object of manufacturing unicellular vegetable life. During the years between 1870 and 1880, this question was thoroughly thrashed out, and at first the balance seemed to be very evenly held between the supporters and the opponents of spontaneous generation. The investigations of the late Professor Tyndall, however, conclusively proved that biogenesis, that is, all life from previous life, is the condition at the present day. But I must add Huxley’s words of warning, viz., “that with organic chemistry, molecular physics, and physiology yet in their infancy, and every day making prodigious strides, it would be the height of presumption for any man to say that the conditions under which matter assumes the qualities called vital, may not some day be artificially brought together.” And further, “that as a matter not of proof but of probability, if it were given me to look beyond the abyss of geologically recorded time, to the still more remote period when the earth was passing through chemical and physical conditions which it can never see again, I should expect to be a witness of the evolution of living protoplasm from nonliving matter.”

The first protoplasm must be extremely ancient, for the remains of sea-weeds are found in the oldest strata, and vegetation implies the manufacture of protoplasm from inorganic matter.

When the earth was in the condition to which Huxley referred, the constantly decreasing heat, and the recurrence of the seasons produced, by slow degrees, changes in the congenital character of the forms of life. Every individual varied somewhat from its predecessors, and those forms which possessed variations most suitable to the environment were the ones which eventually survived. The transition from the protophyta, the lowest class of vegetable life, to the protozoa, the lowest class of animal life, must have been a very simple matter in the condition in which the earth then was. Indeed, today the difference between the lowest microscopic animals and the lowest microscopic plants is by no means clearly defined.

Innumerable hosts of life made their appearance upon our planet while the surface was going through the cooling process, and they were, at first, of course, of the most primitive kind. But the same laws were always at work, viz., no two living things were exactly alike when they made their appearance upon this earth, although the differences between several forms might be very slight. Variation was, and is, the order of the day.

The individuals which possessed variations in accordance with the environment persisted, while those having injurious variations had a tendency to disappear. Congenital variations were (and are) transmitted with great certainty. This is Mr. Darwin’s “Process of Natural Selection,” called by Mr. Spencer “The Survival of the Fittest.”

The other Darwinian factor in evolution is Sexual Selection. It is that department of Natural Selection in which sex is especially concerned. Anything which exhibits the prowess or beauty of the one sex attracts the other, and decides the preference for one individual over another, with the result that those individuals which are unattractive to the opposite sex are unable to reproduce their kind. The importance of this factor will be appreciated if I give an extract from Darwin’s “Descent of Man” (Vol. II., p. 367). “For my own part,” wrote our great master, “I conclude that of all the causes which have led to the differences in external appearance between the races of men, and to a great extent between man and the lower animals, sexual selection must have been by far the most efficient.”

As I have already said, Darwin neither invented nor discovered the doctrine of Evolution. But he placed it upon a firm foundation by the discovery of the two great factors to which I have referred, and, by incessant observation and indomitable energy, he demonstrated the truth of them beyond any reasonable doubt.

The proofs of the truth of Evolution are of two kinds—palaeontological and embryological. The palaeontological evidence has found its way into popular books, and even into some of the literary newspapers. The history of the horses, of the crocodiles, of the rhinoceros is known in detail. All the stages have been found which intervene between the four-toed Eohippos of the Lower Eocene and the zebra and horse of the present day. Thanks to the late Professor Marsh, of Yale, not only are the successive steps in the evolution of the foot-structure preserved, but so also are the various stages in the evolution of the teeth. The occasional appearance of a three-toed horse points very plainly to a three-toed progenitor, a striking example of atavism, that is, the reappearance of a characteristic which has “skipped” one or more generations.

If the principle of heredity be true, one would expect to find in the development of animals and plants, traces of the line of descent. “If Evolution be true, one ought to find, following back the development of the egg, that specific details would vanish and give rise to more generalized features; that the earlier the stages, the more the embryos of related forms would resemble each other.” This is exactly what is found, there being, in a vast number of instances, a remarkable parallel between the palaeontological record and the embryological evidence. A detailed examination of the facts would not be intelligible to anybody who is not a practical biologist; but I am fully warranted in asserting that every organism in the course of its life-history (technically called ontogeny) is a recapitulation of the history of the race—technically known as phylogeny.

There is other evidence in abundance. The phenomena named atavism is a part of that evidence. Almost everybody has seen well-defined and regular stripes upon horses, and nobody doubts that they indicate a zebra-like ancestor. Again, in the inner side of the human eye is a little red fold, known as the plica semilunaris, the remnant of an ancestor which possessed a third eyelid, similar to that possessed by some reptiles and birds of to-day.

Who are the supporters of the doctrine of Evolution? Practically the whole scientific world. The late Professor Marsh, the distinguished palaeontologist, when president of the American Association for the Advance of Science in 1878, said:

“I need offer no argument for Evolution, since to doubt evolution is to doubt science, and science is only another name for the truth.” Professor Marsh meant, of course, not that evolution is to be taken “on trust,” but that it has been so thoroughly proved that new arguments in support of it are unnecessary.

Concerning Natural Selection, sometimes called Darwinism, the late Professor Huxley said (quotation from Darwin’s “Life”): “I venture to affirm that so far as all my knowledge goes, all the ingenuity and all the learning of the hostile critics have not enabled them to adduce a single fact of which it can be said this is irreconcilable with the Darwinian theory.”

I occasionally hear the old argument that species are immutable—that a species is something which never changes. It seems a little late in the day to revive this contention, but it is necessary to be prepared with a reply. The critics of Darwin’s theory of “the Origin of Species by Natural Selection” have always refused to give a tangible definition of the word “species,” and, as a result, the real difficulty turns upon that point. What is a species? Linnaeus said: “There are as many species as an infinite Being created at the beginning,” a statement which is a confession of faith, and not a scientific definition. We must remember, of course, that Linnaeus died as long ago as 1778. The truth is that all the various tests for species have proved faulty, that of the fertility of hybrids having little more value than many of the other so-called “tests.” In classification, the word “species” means the lowest subdivision to which a name is usually applied, and to aid the zoologist’s or botanist’s memory, some system of classification is, I need not say, an absolute necessity.

According to the view of the anti-evolutionists, most of whom are not scientific men, descendants of a common ancestor must belong to the same species. Nevertheless, the late Mr. Romanes has shown that the rabbits of Porto Santo, an island in the Atlantic, about twenty-five miles from Madeira, descended from the European stock of nearly 500 years ago, will no longer breed with their continental cousins.

When we remember that some wild animals will not breed in captivity, the idea of sterility as a test of species seems utterly unscientific. I venture to say that there can be no accurate definition of species in terms of physiology, for every individual has its peculiarities, chemical as well as physical, and the real difficulty is to decide when these peculiarities are important enough to make it useful to give a precise name to their possessors. Assume for a moment that a species is a group of individuals agreeing in essential characters which remain constant from one generation to another. But what are essential characters and how much constancy is demonstrated? Upon these points no two biologists are likely to agree. For example, taking the birds of Germany, Bechstein says there are 367 species; Brehm says there are 900. According to Reichenbach there are 379, and Meyer and Wolf tell us there are 406.

The idea of a species is based upon structural resemblances between individuals, and the degree of importance attached to these depends upon the mind of the particular observer.

There are two reasons why nobody has seen one species turn into another. The first is that until the word “species” is satisfactorily defined, instances of the evolution of new forms cannot be supplied. Secondly, as nobody lives much beyond a hundred years at the most—a mere moment in Nature—our ability to witness marked changes in animals or plants is extremely limited. Minor changes, of course, are frequently noticed. I ask the reader to remember, however, that the flower-garden and the farm-yard are in an artificial condition, Natural Selection having ceased. For instance, the duck which has defective wings when hatched has as good a chance of surviving as the duck with powerful wings.

Who are the opponents of the doctrine of Evolution? In the scientific world they are difficult to find. Professor Virchow, of Berlin, the distinguished pathologist must, I think, be classed as one, although his verdict is really “not proven.” Professor Haeckel, however, has pointed out that the opinion of a pathologist, no matter how eminent, upon the subject of evolution cannot carry much weight.

Until recently we had with us two men of science whose opposition to some portion of the doctrine of evolution was of importance. These men were Sir William Dawson, the Canadian geologist, and Mr. Mivart, the English anatomist. Both of these gentlemen have died within the past two years.

Having now written a brief outline of the doctrine of Evolution, I believe that I cannot do better than conclude this very imperfect sketch with a quotation from the immortal Shakespeare:

“The truth can never be confirmed enough,

Though doubts did ever sleep.”

Lawrence Irwell.