Life of Charles Darwin Part 1

Life of Charles Darwin.

by G. T. (George Thomas) Bettany.

NOTE.

Darwin revealed himself so largely in his books, that a vivid picture of much of his life can be extracted from them. Thus it has been found possible to combine much biographical interest with sketches of his most important works. Like other biographers of Darwin, I am much indebted to Mr. Woodall's valuable memoir, contributed to the Transactions of the Shropshire Archaeological Society. But original authorities have been consulted throughout, and the first editions of Darwin's books quoted, unless the contrary is explicitly stated. I am greatly obliged to Messrs. F. Darwin and G. J. Romanes for kindly permitting me to quote from Mr. Darwin's letters to Mr. Romanes. I must also express my thanks to my friends, Mr. Romanes and Prof. D'Arcy W. Thompson, for doing me the great service of looking over the proof-sheets of this book.

LIFE OF DARWIN.

CHAPTER I.

If ever a man's ancestors transmitted to him ability to succeed in a particular field, Charles Darwin's did. If ever early surroundings were calculated to call out inherited ability, Charles Darwin's were. If ever a man grew up when a ferment of thought was disturbing old convictions in the domain of knowledge for which he was adapted, Charles Darwin did.

If ever a man was fitted by worldly position to undertake unbia.s.sed and long-continued investigations, Charles Darwin was such a man. And he indisputably found realms waiting for a conqueror. Yet Darwin's achievements far transcend his advantages of ancestry, surroundings, previous suggestion, position. He stands magnificently conspicuous as a genius of rare simplicity of soul, of unwearied patience of observation, of striking fertility and ingenuity of method, of unflinching devotion to and belief in the efficacy of truth. He revolutionised not merely half-a-dozen sciences, but the whole current of thinking men's mental life.

The Darwins were originally a Lincolnshire family of some position, and being royalists suffered heavy losses under the Commonwealth. The third William Darwin (born 1655), whose mother was a daughter of Erasmus Earle, serjeant-at-law,[1] married the heiress of Robert Waring, of Wilsford, Notts, who also inherited the manor of Elston, near Newark, in that county, which still remains in the family. Robert Darwin, second son of this William Darwin, succeeded to the Elston estate, and was described by Stukeley, the antiquary, as "a person of curiosity," an expression conveying high commendation. His eldest son, Robert Waring Darwin, studied botany closely, and published a "Principia Botanica,"

which reached a third edition; but his youngest son, Erasmus, born 1731, was destined to become the first really famous man of the family.

Erasmus Darwin's personal characteristics, his medical talents, and his poetic writings were such as to overshadow, for his own generation, his scientific merit. We have not s.p.a.ce here to describe his career and his works, which has been so well done by his grandson, and by Ernst Krause ("Erasmus Darwin," 1879). Horace Walpole regarded his description of creation in "The Botanic Garden" (part i., canto 1, lines 103-114) as the most sublime pa.s.sage in any language he knew: and _The Edinburgh Review_ (vol. ii., 1803, p. 501) says of his "Temple of Nature": "If his fame be destined in anything to outlive the fluctuating fashion of the day, it is on his merit as a poet that it is likely to rest; and his reveries in science have probably no other chance of being saved from oblivion but by having been 'married to immortal verse.'"

The present age regards it as next to impossible to write science in poetry; although few have succeeded better in the attempt than Erasmus Darwin. It is singular that he should have partially antic.i.p.ated his ill.u.s.trious grandson's theories, but without supporting them by experimental proof or by deep scientific knowledge. Suffice it to say now, that Erasmus contemplated to a great extent the same domain of science as Charles Darwin, having also a mechanical turn; and was educated at Edinburgh and Cambridge. His observations on Providence in 1754, when only twenty-three, in commenting on his father's death, are very interesting to compare with his grandson's att.i.tude: "That there exists a superior Ens Entium, which formed these wonderful creatures, is a mathematical demonstration. That He influences things by a particular providence is not so evident. The probability, according to my notion, is against it, since general laws seem sufficient for that end.... The light of Nature affords us not a single argument for a future state: this is the only one, that it is possible with G.o.d, since He who made us out of nothing can surely re-create us; and that He will do this we humbly hope." He published an ode against atheism, with which he has strangely enough often been charged, beginning--

"Dull atheist, could a giddy dance Of atoms lawless hurl'd Construct so wonderful, so wise, So harmonised a world?"

and his moral standpoint is shown by the declaration that "the sacred maxims of the author of Christianity, 'Do as you would be done by,' and 'Love your neighbour as yourself,' include all our duties of benevolence and morality; and if sincerely obeyed by all nations, would a thousandfold multiply the present happiness of mankind" ("Temple of Nature," 1803, p. 124). His princ.i.p.al poetical writings were "The Botanic Garden," in two parts; Part I. containing "The Economy of Vegetation," first published in 1790; and Part II., "The Loves of the Plants," in 1788, before the first part had appeared. "The Temple of Nature, or the Origin of Society," was published after his death, in 1803. His chief prose works are "Zoonomia, or the Laws of Organic Life,"

in two volumes, 1794-6, the second volume being exclusively medical; and "Phytologia, or the Philosophy of Agriculture and Gardening," 1800. All these books are in quarto, with plates. His views on species are referred to on pages 66 and 67. [Transcriber's Note: Footnote 6.]

Robert Waring Darwin, third son of Erasmus by his first wife, Mary Howard, was born in 1766. As a boy he was brought much into a.s.sociation with the Wedgwoods of Stoke, Josiah Wedgwood being one of Erasmus Darwin's most intimate friends. In 1779 Robert, already destined to be a doctor, stayed at Etruria for some time, sharing with Wedgwood's children in Warltire's private chemical instruction; and Josiah Wedgwood wrote at this time: "The boys drink in knowledge like water, with great avidity." Before he was twenty Robert Darwin had taken his medical degree with distinction at Edinburgh, where he had the advantage of the lectures of Black, Cullen, and Gregory, and had also studied at Leyden, and travelled in Germany. In 1786 his father set him up in practice at Shrewsbury, leaving him with twenty pounds, which was afterwards supplemented by a similar sum from his uncle, John Darwin, Rector of Elston. On this slender capital he contrived to establish himself, in spite of severe compet.i.tion; and his burly form and countenance, as he sat in his invariable yellow chaise, became well known to every man, woman, and child around Shrewsbury for many miles. Before long, no one thought of sending to Birmingham for a consultant, and Dr. Darwin was for many years the leading Shropshire physician, and acc.u.mulated an abundant fortune.

According to his son Charles, Robert Darwin "did not inherit any apt.i.tude for poetry or mechanics, nor did he possess, as I think, a scientific mind. He published, in vol. lxxvi. of the 'Philosophical Transactions,' a paper on Ocular Spectra, which Wheatstone told me was a remarkable production for the period; but I believe that he was largely aided in writing it by his father. He was elected a Fellow of the Royal Society in 1788. I cannot tell why my father's mind did not appear to me fitted for advancing science, for he was fond of theorising, and was incomparably the most acute observer whom I ever knew. But his powers in this direction were exercised almost wholly in the practice of medicine and in the observation of human character. He intuitively recognised the disposition or character, and even read the thoughts, of those with whom he came into contact, with extraordinary astuteness. This skill partly accounts for his great success as a physician, for it impressed his patients with belief in him; and my father used to say that the art of gaining confidence was the chief element in a doctor's worldly success."

Sensitive, sociable, a good talker, high-spirited and somewhat irascible, a man who admitted no one to his friendship whom he could not thoroughly respect, the friend of the poor, prescribing gratuitously to all who were needy, pre-eminent for sympathy, which for a time made him hate his profession for the constant suffering it brought before his eyes--such was Charles Darwin's father. Miss Meteyard, in her "Group of Englishmen," 1871, gives a vivid picture of the old doctor, his acknowledged supremacy in Shrewsbury, his untiring activity and ubiquity, his great dinner parties, his liberal and rather unpopular opinions, tolerated for the sake of his success in curing his patients.

His face, powerful, unimpa.s.sioned, mild, and thoughtful, was always the same as he rolled through the streets and lanes, for he sat "as though carved in stone." His love of children was marked. "He would address them in his small, high-pitched falsetto voice, and if their answers pleased him he would reply; and occasionally, lifting them on to a chair or table, he would measure their heads with his broad hand, as though reading character, and mentally prognosticating their future fate."

The successful doctor bought a piece of land near the Holyhead road, and built on it a large square house, of plain architecture, which from its charming position, a hundred feet above the Severn, received the name of "The Mount."[2] Having thus provided the nest, in 1796 he brought home his wife, Susannah Wedgwood, eldest daughter of the celebrated potter, to whom he was married at Marylebone Church on April 18th.

The character and education of Charles Darwin's mother is a matter of considerable interest, notwithstanding that her death when he was only eight years old cut short her opportunities of influencing him. She was born at Burslem in January, 1765, and a year after her father describes her as a "fine, sprightly la.s.s:" she became his best-beloved child. She was partly educated in London, under the eye of her father's partner, the accomplished Thomas Bentley, in whose heart she won as tender a place as in her father's. Later she continued her education at home with her brothers, under good tuition. Many visits were exchanged between the Darwins and the Wedgwoods, and old Erasmus Darwin became very fond of Miss Wedgwood. By the time of her marriage she was matured by much intercourse with notable people, as well as by extensive reading, and from her experience of London society and varied travel in England was well fitted to shine as the county doctor's wife. From her father, who died in 1795, she had doubtless inherited, in addition to a handsome fortune, many valuable faculties, and probably she transmitted more of them to her son Charles than she herself manifested. Josiah Wedgwood, over whose career it would be delightful to linger, is well described by Miss Meteyard in words which might be precisely applied to Charles Darwin, as "patient, stedfast, humble, simple, unconscious of half his own greatness, and yet by this very simplicity, patience, and stedfastness displaying the high quality of his moral and intellectual characteristics, even whilst insuring that each step was in the right direction, and firmly planted." A truly experimental genius in artistic manufacture, Wedgwood foreshadowed a far greater experimental genius in science.

Before her famous son was born, however, Mrs. Darwin's health had begun to fail, and in 1807 she wrote to a friend: "Every one seems young but me." Her second son (four daughters having preceded him) was born at The Mount on February 12, 1809, and christened "Charles Robert," at St.

Chad's Church, Shrewsbury, on November 17th following. No doubt her declining health emphasised her attachment to home pursuits, to quiet reading, to the luxuriant garden, and to her numerous domestic pets. The beauty, variety, and lameness of The Mount pigeons was well known in the town and far beyond. Mr. Woodall states that one of Darwin's schoolfellows, the Rev. W. A. Leighton, remembers him plucking a plant and recalling one of his mother's elementary lessons in botany. Too soon however the mother was taken from The Mount; she died in July, 1817, when Charles was between eight and nine years old.

The eldest son of Dr. Robert Darwin, on whom the grandfather's name of Erasmus had been bestowed, is notable as the intimate friend of the Carlyles. "He had something of original and sarcastically ingenious in him," says Carlyle, in his "Reminiscences," "one of the sincerest, naturally truest, and most modest of men.... E. Darwin it was who named the late Whewell, seeing him sit, all ear (not all a.s.sent), at some of my lectures, 'The Harmonious Blacksmith.' My dear one had a great favour for this honest Darwin always; many a road to shops, and the like, he drove her in his cab, in those early days when even the charge of omnibuses was a consideration, and his spa.r.s.e utterances, sardonic often, were a great amus.e.m.e.nt to her. 'A perfect gentleman,' she at once discerned him to be, and of sound worth and kindliness, in the most unaffected form." He died in 1881, aged 77, leaving no memorial to the public of his undoubtedly great abilities. Like his younger brother, he was a member of Christ's College, Cambridge, where he graduated M.B., in 1828.

Early in 1817, the closing year of his mother's life, Charles Darwin was placed at school with the Rev. George Case, minister of the Shrewsbury Unitarian church, to which the Darwins were attached, in this resembling the Wedgwoods. At midsummer, 1818, however, the boy entered Shrewsbury Grammar School, then under Samuel Butler, afterwards Bishop of Lichfield. Cla.s.sics, as ever, formed the staple of the instruction there afforded, and proved but little to the future naturalist's taste.

Unfortunately for the repute of English schools, Charles Darwin was little benefited by his schooling; and Euclid, then an extra subject, const.i.tuted, to his mind, the only bit of real education Shrewsbury school gave him. Seventy years later, the study of mother earth and her teeming productions, which Darwin made so attractive, is still but scantily represented in the instruction afforded by our great schools.

Thus out of sympathy with the prevalent studies, the youth showed no fondness for his schoolfellows' sports. He was reserved, frequently lost in thought, and fond of long solitary rambles, according to one schoolfellow, the Rev. W. A. Leighton; another, the Rev. John Yardley, Vicar of St. Chad's, Shrewsbury, remembers him as cheerful, good-tempered, and communicative. One of the recorded incidents of his boyish days is a fall from the old Shrewsbury wall, while walking in a "brown study." Even at this early period he was fond of collecting objects which many schoolboys delight in, such as sh.e.l.ls and minerals, seals, franks, and coins; and the mechanical apt.i.tude derived from both the Darwins and the Wedgwoods was manifested by keen interest in mechanism. One especially remembered youthful treat was when his uncle Josiah Wedgwood explained to him the principle of the vernier. No doubt the pigeons, the exotics, the shrubs and flowers of his father's grounds impressed themselves indelibly on the boy's mind and unconsciously prepared him for his future. Schooldays were for him fortunately not protracted, for in 1825, at the age of sixteen, he went to Edinburgh University, where his father and grandfather had likewise studied, with the idea of devoting himself to medicine. The youth of sixteen was well equipped with the results of long thinking and observing rather than with book-learning, and was prepared to play an independent part without noise and show, a.s.similating that which commended itself to his mind, and rejecting that which found no appropriate soil in him, in a manner characteristic of genuine originality.

FOOTNOTES:

[1: This is the Erasmus Earle who forms the subject of "A Lawyer's Love Letters," in _The National Review_, February, 1887.

Letters of his are also printed in the Tenth Report of the Historical MSS. Commission.]

[2: "The house is seen," says Mr. Woodall, "from the line immediately beyond the low tower of St. George's Church. Visitors who make a pilgrimage there, after crossing the Welsh Bridge, follow the main street until St. George's Church is pa.s.sed, and the continuous line of houses ceases. The next carriage drive, on the right, cutting in two a lofty side-walk, is the entrance to The Mount. A short street of new houses, near St. George's Church, has been called 'Darwin Street;' as yet the only public recognition in the town of the greatest of Salopians. A memorial of a more private character has been placed in the Unitarian Chapel, in the form of a tablet bearing the following inscription:--'To the memory of Charles Robert Darwin, author of "The Origin of Species," born in Shrewsbury, February 12th, 1809. In early life a member and constant worshipper in this church. Died April 19th, 1882.' Mrs. Darwin, we believe, was not strict in her adhesion to the communion in which she had been brought up, but often attended St.

Chad's Church, where Charles and his brother were baptized."]

CHAPTER II.

When Charles Darwin went to Edinburgh, the university was not in one of its palmiest periods. The medical professors failed to attract him to their profession, and two years of Edinburgh satisfied him that medicine should not absorb him. With natural history the case was different. Its attractiveness for Darwin increased. He found congenial companionship in the Edinburgh Plinian Society, and Mr. W. F. Ainsworth relates (in _The Athenaeum_, May 13, 1882) that Darwin and himself made frequent excursions on the sh.o.r.es of the Firth of Forth in pursuit of objects of natural history, sometimes visiting the coasts of Fifeshire, and sometimes the islands off the coast. On one occasion, accompanied by Dr.

Greville, the botanist, they went to the Isle of May, and were both exceedingly amused at the effect produced upon the eminent author of the Scottish Cryptogamic Flora by the screeching of the kittiwakes and other water-fowl. He had actually to lie down on the greensward to enjoy his prolonged cachinnation. On another occasion the young naturalists were benighted on Inch Keith, but found refuge in the lighthouse.

Darwin was now not merely a collector and exploring naturalist, but he observed biological facts of importance. On the 27th of March, 1827, he made a communication to the Plinian Society on the ova, or rather larvae, of the Fl.u.s.tra or sea-mat, a member of the cla.s.s Polyzoa, forming a continuous mat-like colony of thousands of organisms leading a joint-stock existence. He announced that he had discovered in these larvae organs of locomotion, then so seldom, now so frequently, known to exist on such bodies. At the same time, he made known that the small black body which until that time had been mistaken for the young state of a species of seaweed, was in reality the egg of _Pontobdella muricata_, a sort of sea-leech. On the 3rd of April following, the discoverer exhibited specimens of the latter creature with eggs and young.

In making these researches, Darwin was no doubt stimulated and aided by the teaching of Dr. Grant, afterwards Professor of Natural History at University College, London, who was then at Edinburgh, making discoveries in the structure of sponges. Professor Jameson, too, who was then forming his splendid museum of natural history, cannot fail to have influenced Darwin somewhat; and we find that the first lecture of the concluding portion of Jameson's zoological course, dealing with "The Philosophy of Zoology," had the suggestive t.i.tle of "The Origin of the Species of Animals." Thus we must acknowledge that already at Edinburgh Darwin was fairly started in the paths of zoological inquiry, and the northern university must be admitted to share with Cambridge, the distinction of being the foster-parent of this giant-child.

Medicine being distasteful, Edinburgh had no other distinctive charms to offer to young Darwin, and he was entered at Christ's College, Cambridge, early in 1828, with the idea of his becoming a clergyman of the Church of England. It might have been thought that there was scant stimulus for a biological student in the Cambridge of that period; but although the old literary and mathematical studies were still the only paths to a degree, there were men of original force and genius at work preparing the ground for a coming revolution. Sedgwick was teaching geology with the fire of a prophet, and Henslow as a botanist was showing that lessons of enthralling interest were to be learned from the humblest flower. Henslow especially attracted young Darwin, who never forgot his old teacher. In the preface to the journal of his voyage in the _Beagle_ he returns his most sincere thanks to Professor Henslow, "who," he says, "when I was an undergraduate at Cambridge, was one chief means of giving me a taste for natural history; who, during my absence, took charge of the collections I sent home, and by his correspondence directed my endeavours--and who, since my return, has constantly rendered me every a.s.sistance which the kindest friend could offer."

No better idea of Darwin's Cambridge days can be given than that which is derived from reading his account of Professor Henslow, contributed to the Rev. L. Jenyns's "Memoirs" of that accomplished man. There can be no doubt, also, that in thus pourtraying the character of another, he was at the same time, as Mr. Romanes puts it, "unconsciously giving a most accurate description of his own."

"I went to Cambridge," wrote Darwin, "early in the year 1828, and soon became acquainted, through some of my brother entomologists,[3] with Professor Henslow, for all who cared for any branch of natural history were equally encouraged by him. Nothing could be more simple, cordial, and unpretending than the encouragement which he afforded to all young naturalists. I soon became intimate with him, for he had a remarkable power of making the young feel completely at ease with him; though we were all awe-struck with the amount of his knowledge. Before I saw him I heard one young man sum up his attainments by simply saying that he knew everything. When I reflect how immediately we felt at perfect ease with a man older and in every way so immensely our superior, I think it was as much owing to the transparent sincerity of his character, as to his kindness of heart, and, perhaps, even still more to a highly remarkable absence in him of all self-consciousness. One perceived at once that he never thought of his own varied knowledge or clear intellect, but solely on the subject in hand. Another charm, which must have struck every one, was that his manner to old and distinguished persons and to the youngest student was exactly the same: to all he showed the most winning courtesy. He would receive with interest the most trifling observation in any branch of natural history, and however absurd a blunder one might make, he pointed it out so clearly and kindly, that one left him in no way disheartened, but only determined to be more accurate the next time.

In short, no man could be better formed to win the entire confidence of the young, and to encourage them in their pursuits.

"His lectures on botany were universally popular, and as clear as daylight. So popular were they, that several of the older members of the university attended successive courses. Once every week he kept open house in the evening, and all who cared for natural history attended these parties, which, by thus favouring intercommunication, did the same good in Cambridge, in a very pleasant manner, as the scientific societies do in London. At these parties many of the most distinguished members of the university occasionally attended; and when only a few were present, I have listened to the great men of those days conversing on all sorts of subjects, with the most varied and brilliant powers.

This was no small advantage to some of the younger men, as it stimulated their mental activity and ambition. Two or three times in each session he took excursions with his botanical cla.s.s, either a long walk to the habitat of some rare plant, or in a barge down the river to the fens, or in coaches to some more distant place, as to Gamlingay, to see the wild lily-of-the-valley, and to catch on the heath the rare natter-jack.

These excursions have left a delightful impression on my mind. He was, on such occasions, in as good spirits as a boy, and laughed as heartily as a boy at the misadventures of those who chased the splendid swallow-tail b.u.t.terflies across the broken and treacherous fens. He used to pause every now and then and lecture on some plant or other object; and something he could tell us on every insect, sh.e.l.l, or fossil collected, for he had attended to every branch of natural history. After our day's work we used to dine at some inn or house, and most jovial we then were. I believe all who joined these excursions will agree with me that they have left an enduring impression of delight on our minds.

"As time pa.s.sed on at Cambridge I became very intimate with Professor Henslow, and his kindness was unbounded; he continually asked me to his house, and allowed me to accompany him in his walks. He talked on all subjects, including his deep sense of religion, and was entirely open. I owe more than I can express to this excellent man. His kindness was steady. When Captain Fitzroy offered to give up part of his own cabin to any naturalist who would join the expedition in H.M.S. _Beagle_, Professor Henslow recommended me as one who knew very little, but who, he thought, would work. I was strongly attached to natural history, and this attachment I owed in large part to him. During the five years'

voyage he regularly corresponded with me, and guided my efforts; he received, opened, and took care of all the specimens sent home in many large boxes; but I firmly believe that, during these five years, it never once crossed his mind that he was acting towards me with unusual and generous kindness.

"During the years when I a.s.sociated so much with Professor Henslow I never once saw his temper even ruffled. He never took an ill-natured view of any one's character, though very far from blind to the foibles of others. It always struck me that his mind could not be even touched by any paltry feeling of vanity, envy, or jealousy. With all this equability of temper and remarkable benevolence, there was no insipidity of character. A man must have been blind not to have perceived that beneath this placid exterior there was a vigorous and determined will.

When principle came into play no power on earth could have turned him one hair's breadth....

"In intellect, as far as I could judge, accurate powers of observation, sound sense, and cautious judgment seemed predominant. Nothing seemed to give him so much enjoyment as drawing conclusions from minute observations. But his admirable memoir on the geology of Anglesea shows his capacity for extended observations and broad views. Reflecting over his character with grat.i.tude and reverence, his moral attributes rise, as they should do in the highest character, in pre-eminence over his intellect."

The young man's modesty is conspicuous in the above narrative. He does not see how his own transparent candour, his desire to learn, his respect for those who were already masters of science, won upon the great men with whom he came in contact. It was by no means as "one who knew very little" that Henslow recommended Darwin to Captain Fitzroy, but as "a young man of promising ability, extremely fond of geology, and indeed all branches of natural history." "In consequence," says Fitzroy, "an offer was made to Mr. Darwin to be my guest on board, which he accepted conditionally. Permission was obtained for his embarkation, and an order given by the Admiralty that he should be borne on the ship's books for provisions. The conditions asked by Mr. Darwin were, that he should be at liberty to leave the _Beagle_ and retire from the expedition when he thought proper, and that he should pay a fair share of the expenses of my table."

Darwin had taken an ordinary or "poll" degree in 1831 and was admitted a Master of Arts in 1837. In the interval he had become truly a Master of Science, which at that time was adequately recognised by no university in the British dominions. The memorable voyage of the _Beagle_, a little barque of 242 tons, was at first delayed by heavy gales which twice drove her back; but she finally sailed from Devonport on December 27, 1831. The object of the expedition was to complete the survey of Patagonia and Tierra del Fuego, to survey the sh.o.r.es of Chili, Peru, and some Pacific Islands, and to carry a chain of chronometrical measurements round the world.

Professor Henslow's interest in his young pupil's progress is shown by the fact that in 1835 (December 1) he printed some extracts from his letters, for distribution among the members of the Cambridge Philosophical Society, in consequence of the notice excited by some geological observations they contained, which had been read before the society on the 16th of November previous. The following points having a personal reference to the traveller may be quoted. On August 15, 1832, Darwin wrote from Monte Video, "I might collect a far greater number of specimens of invertebrate animals if I took up less time over each: but I have come to the conclusion that two animals with their original colour and shape noted down will be more valuable to naturalists than six with only dates and place." Here we see the accuracy which was the source of much of his after-success. On November 24, 1832, he writes from the same place, "As for one little toad, I hope it may be new, that it may be christened 'Diabolicus.' Milton must allude to this very individual, when he talks of 'squat like a toad.'" In March, 1834, writing from East Falkland Island, he says, "The whole of the east coast of the southern part of South America has been elevated from the ocean since a period during which mussels have not lost their blue colour."