Part 42

"All the Animals of each class are formed on the same plan....

"Why should the animals of one class (such as the vertebrate or back-boned class) be formed all on one plan, even to the most minute bones; so that the wing of a bat, the front leg of a horse, the hand of a man, and the flapper of a porpoise, are all made of the same bones, which have either grown together, or lengthened and spread apart, according to the purpose they serve? And, more curious still, why should some animals have parts which are of no use to them, but only seem to be there because other animals of the same class also have them? Thus the whale has teeth like the other mammalia, but they never pierce through the gum; and the boa-constrictor has the beginnings of hind legs, hidden under its skin, though they never grow out. Here, again, it seems extraordinary, if a boa-constrictor and a whale were created separately, that they should be made with organs which are quite useless; while, on the other hand, if they were descended from the same ancestor, as other reptiles and mammalia who have teeth and hind legs, they might be supposed to have inherited these organs....

"Embryos of animals alike in Structure.

"Another still more remarkable fact was that pointed out by Von Baer, that the higher animals, such as quadrupeds, before they are perfectly formed, cannot be distinguished from the embryos of other and lower animals, such as fish and reptiles. If animals were created separately, why should a dog begin like a fish, a lizard, and a bird, and have at first parts which it loses as it grows into its own peculiar form?

"Living animals of a country agree with the fossil ones....

"We know that certain animals are only found in particular countries; kangaroos and pouched animals, for example, in Australia, and sloths and armadillos in South America. Now, it is remarkable that all the fossil quadrupeds in Australia are also pouched animals, though they are of different kinds and larger in size than those now living; and in the same way different species of sloth and armadillos are found fossil in South America; while in the rocks of Europe fossil mammalia are found, only slightly different from those which are living there now." It seems natural to conclude that the living have descended from the fossils.

The study of the rocks has produced other "missing links" in the succession of animal life. Professor Huxley, in some lectures given in New York in 1876, described the Hesperornis, found in the western rocks,--a huge bird, five or six feet in length, with teeth like a reptile. In England a fossil reptile has been found, the Archaeopteryx, having a reptile-like tail, with a fringe of feathers on each side, and teeth, "occupying a midway place between a bird and a reptile." Flying reptiles have been found, and reptiles which walked on their hind legs. Those who have visited Yale and Amherst Colleges must have seen the huge bird-tracks or reptile foot-prints taken from the rocks in the Connecticut valley.

Professor Huxley showed the probable descent of the horse with its hoofed foot from the extinct three-toed Hipparion of Europe, and that from the four-toed Orohippus of the Eocene formation. He declared it probable that a five-toed horse would be found, and Professor Marsh, in the West, has found the Eohippus, corresponding very nearly to Professor Huxley's description.

The question among naturalists was, "How can plants and animals have become thus changed?" Darwin showed how it was possible to effect most of these changes by "natural selection," or the choosing of the best to survive in the struggle for existence. As man by grafting secures the finest fruit, and by care in animal life the swiftest horses for speed as well as the strongest for labor, so nature selects her best for the higher development of the race.

Darwin says, "There is no exception to the rule that every organic being naturally increases at so high a rate that, if not destroyed, the earth would soon be covered by the progeny of a single pair. Even slow-breeding man has doubled in twenty-five years, and, at this rate, in less than a thousand years there would literally not be standing-room for his progeny.... The elephant is reckoned the slowest breeder of all known animals; it will be safest to assume that it begins breeding when thirty years old, and goes on breeding till ninety years old, bringing forth six young in the interval, and surviving till one hundred years old; if this be so, after a period of from 740 to 750 years, there would be nearly nineteen million elephants alive, descended from the first pair."

In various ways the weakest are destroyed. Darwin, on a piece of ground three feet long and two wide, says, "I marked all the seedlings of our native weeds as they came up, and, out of 357, no less than 295 were destroyed, chiefly by slugs and insects."

He gives this interesting instance of the struggle for existence. "I find from experiments that humble-bees are almost indispensable to the fertilization of the heart's-ease, for other bees do not visit this flower.... Humble-bees alone visit red clover, as other bees cannot reach the nectar.... Hence we may infer as highly probable that, if the whole genus of humble-bees became extinct or very rare in England, the heart's-ease and red clover would become very rare, or wholly disappear. The number of humble-bees in any district depends in a great measure upon the number of field-mice, which destroy their combs and nests; the number of mice is largely dependent, as every one knows, on the number of cats." Hence, as Mr. Darwin shows, the frequency of certain flowers in a district may depend upon the number of cats!

Darwin showed, by most interesting experiments with pigeons, that the various breeds come from the wild rock-pigeon; that dogs are descended, probably, from the wolf; that different varieties can be produced and perpetuated under changing conditions of life; that species are only well marked and permanent varieties. He showed how organs can be changed by use or disuse; such as, the erect ears of wild animals become drooping under domestication; or moles have only rudimentary eyes, covered with skin or fur, because not needed for sight.

In the "Origin of Species," the theory of evolution received proof which was so nearly incontrovertible that the subject was brought prominently before the world as never before. Mr. Alfred Russell Wallace, an able scientist, came to the same conclusion as Darwin in regard to the power of "Natural Selection," and published, at the same time as the "Origin," an essay "On the Tendency of Varieties to depart indefinitely from the Original Type."

At once Darwin was attacked from every quarter. Probably not since Galileo showed that the earth moves round the sun has a man been so censured and persecuted for his opinions as was Darwin. He was declared atheistic, unsettling the Christian belief, and opposed to the teachings of the Bible. Professor Asa Gray of Cambridge, Mass., a devoted Christian and able scientist, defended and explained Darwin's views, now published in "Darwiniana," claiming that the doctrine of evolution is in no wise opposed to the power and goodness of the Almighty, and quotes Charles Kingsley's words: "We know of old that God was so wise that he could make all things; but behold, he is so much wiser than even that, that he can make all things make themselves." Kingsley wrote Darwin: "I have gradually learnt to see that it is just as noble a conception of Deity to believe that he created primal forms capable of self-development into all forms needful pro tempore and pro loco, as to believe that he required a fresh act of intervention to supply the lacunas which he himself had made. I question whether the former be not the loftier thought." Gray believed that "to do any work by an instrument must require, and therefore presuppose, the exertion rather of more than of less power than to do it directly." Darwin said, "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." Darwin always felt grateful to Asa Gray for his defence. He wrote him: "I declare that you know my book as well as I do myself; and bring to the question new lines of illustration and argument, in a manner which excites my astonishment and almost my envy!... I said, in a former letter, that you were a lawyer, but I made a gross mistake; I am sure that you are a poet. No, I will tell you what you are, a hybrid, a complex cross of lawyer, poet, naturalist, and theologian!"

Darwin wisely made no reply to his critics. He said, years later: "My views have often been grossly misrepresented, bitterly opposed and ridiculed, but this has been generally done, as I believe, in good faith. On the whole, I do not doubt that my works have been over and over again greatly overpraised. I rejoice that I have avoided controversies, and this I owe to Lyell, who, many years ago, in reference to my geological works, strongly advised me never to get entangled in a controversy, as it rarely did any good, and caused a miserable loss of time and temper.

"Whenever I have found out that I have blundered, or that my work has been imperfect, and when I have been contemptuously criticised, and even when I have been overpraised, so that I have felt mortified, it has been my greatest comfort to say hundreds of times to myself, 'that I have worked as hard and as well as I could, and no man can do more than this.'"

The "Origin" has been translated into French, German, Italian, Dutch, Russian, Swedish, and many other languages. Huxley says of it, "Even a cursory glance at the history of the biological sciences during the last quarter of a century is sufficient to justify the assertion that the most potent instrument for the extension of the realm of natural knowledge which has come into men's hands since the publication of Newton's 'Principia' is Darwin's 'Origin of Species.'"

The year after the "Origin" was published, Darwin began arranging his notes for his two large volumes, "Variation of Animals and Plants under Domestication," which, however, were not published till 1868. On these two books he spent over four years. They are a wonderful collection of facts, gathered from books and from his own marvellous experiments and observations, confirming and illustrating the law of "Natural Selection" given in the "Origin."

Darwin had already received the Copley medal of the Royal Society, the greatest honor a scientific man can receive in England, and the Prussian Order "Pour le Merite," founded by Frederick II. The order consists of thirty German members and a few distinguished foreigners. In 1862 the "Fertilization of Orchids" was published, which, required ten months of labor. In this work Darwin took the utmost delight. He wrote to a friend who had sent him some of these flowers: "It is impossible to thank you enough. I was almost mad at the wealth of Orchids.... I never was more interested in any subject in my life than in this of Orchids." The peculiarities of the flowers therein described, as Darwin says, "transcend in an incomparable manner the contrivances and adaptations which the most fertile imagination of man could invent."

In the "Origin" he describes an orchid which "has part of its labellum or lower lip hollowed out into a great bucket, into which drops of almost pure water continually fall from two secreting horns which stand above it; and when the bucket is half full the water overflows by a spout on one side. The basal part of the labellum stands over the bucket, and is itself hollowed out into a sort of chamber with two lateral entrances; within this chamber there are curious fleshy ridges. The most ingenious man, if he had not witnessed what takes place, could never have imagined what purpose all these parts serve. But Dr. Crueger saw crowds of large humble-bees visiting the gigantic flowers of this orchid, not in order to suck nectar, but to gnaw off the ridges within the chamber above the bucket; in doing this they frequently pushed each other into the bucket, and, their wings being thus wetted, they could not fly away, but were compelled to crawl out through the passage formed by the spout or overflow.... The passage is narrow, and is roofed over by the column, so that a bee, in forcing its way out, first rubs its back against the viscid stigma and then against the viscid glands of the pollen-masses. The pollen-masses are thus glued to the back of the bee which first happens to crawl out through the passage of a lately expanded flower, and are thus carried away....

"When the bee, thus provided, flies to another flower, or to the same flower a second time, and is pushed by its comrades into the bucket and then crawls out by the passage, the pollen-mass necessarily comes first into contact with the viscid stigma, and adheres to it, and the flower is fertilized. Now at last we see the full use of every part of the flower; of the water-secreting horns, of the bucket half full of water, which prevents the bees from flying away, and forces them to crawl out through the spout, and rub against the properly placed viscid pollen-masses and the viscid stigma."

Darwin said: "The Botanists praise my Orchid-book to the skies.... There is a superb, but, I fear, exaggerated, review in the 'London Review.' But I have not been a fool, as I thought I was, to publish; for Asa Gray, about the most competent judge in the world, thinks almost as highly of the book as does the 'London Review.'"

Darwin wrote several other books on plants. "The Movements and Habits of Climbing Plants" was published in 1875; "Insectivorous Plants," in 1875; "Effects of Cross and Self-Fertilization," in 1876; "The different Forms of Flowers on Plants of the Same Species," in 1877; "The Power of Movement in Plants," in 1880.

When writing his "Different Forms of Flowers," he said, "I am all on fire at the work;" and of "Insectivorous Plants," "I have been working like a madman at Drosera. Here is a fact for you which is certain as you stand where you are, though you won't believe it, that a bit of hair, 1/78000 of one grain in weight, placed on gland, will cause one of the gland-bearing hairs of Drosera to curve inwards, and will alter the condition of the content of every cell in the foot-stalk of the gland."

But he was growing tired with his constant and multifarious labors. He wrote to Hooker: "You ask about my book, and all that I can say is that I am ready to commit suicide; I thought it was decently written, but find so much wants rewriting that it will not be ready to go to printers for two months, and will then make a confoundedly big book. Murray will say that it is no use publishing in the middle of summer, so I do not know what will be the upshot; but I begin to think that every one who publishes a book is a fool."

In 1871 the "Descent of Man" was published. He worked on this book three years, and he wrote to his friend, Sir J. D. Hooker, that it has "half killed" him. For the first edition Darwin received over seven thousand dollars. It had an immense circulation in England and America, and created a furor in Germany.

Darwin believed "that man is descended from a hairy quadruped, furnished with a tail and pointed ears, probably arboreal in its habits, and an inhabitant of the Old World. This creature, if its whole structure had been examined by a naturalist, would have been classed among the quadrumana, as surely as would the common and still more ancient progenitor of the Old and New World monkeys.