Alfred Russel Wallace

by Peter Raby

  To Wallace, the letter must have seemed like an open invitation to continue the exchanges, from a man who was thinking along the same lines. He did not have many scientific correspondents – Bates, of course, but that was necessarily a slow-moving and uncertain business. He neatly returned the ball, expressing satisfaction that his ‘views on the order of succession of species’ were in accordance with Darwin’s:

  The mere statement & illustration of the theory in that paper is of course but preliminary to an attempt at a detailed proof of it, the plan of which I have arranged, & in part written, but which of course requires much [research in English] libraries & collections, a labour which I look –14

  The fragment ends, but Darwin must have been reassured that Wallace did not intend to write a proper book until he had returned from his travels: no competition, apparently, from that quarter.

  On the other side of the world, on the Amazon, Bates had now read Wallace’s Sarawak paper. ‘I was startled at first to see you already ripe for the enunciation of the theory,’ he commented. ‘You can imagine with what interest I read and studied it, and I must say that it is perfectly well done. The idea is like truth itself, so simple and obvious that those who read and understand it will be struck by its simplicity; and yet it is perfectly original.’ Then he added, ‘The theory I quite assent to, and, you know, was conceived by me also, but I profess that I could not have propounded it with so much force and completeness.’15 Was there a mild rebuke in that ‘was conceived by me also’? Wallace had made no acknowledgement to Bates, on a line of enquiry which for him had its origins in 1845 during his various discussions with Bates and, almost certainly, with Spruce on the Amazon. Like Wallace, Bates was turning over the question of species and varieties, and the effect of a particular locality:

  What a noble subject would be that of a monograph of a group of beings peculiar to one region but offering different species in each province of it – tracing the laws which connect together the modifications of forms and colour with the local circumstances of a province or station – tracing as far as possible the actual affiliation of the species.

  Tracing the actual affiliation – Bates was closing on the key issue of ‘how’.

  Life aboard the Dutch mail boat that took Wallace from Macassar to Banda and Amboyna was comparatively luxurious. In spite of his previous praise of the simple life, he put up with the succession of meals, coffee, gin and bitters, claret and beer that punctuated European shipboard routine. They called briefly at Timor, and at Banda, before reaching Amboyna (Ambon), the capital of the Moluccas. He had, as usual, letters of introduction, and found two local naturalists, both doctors: Dr Mohnike specialised in beetles – his collection included magnificent Japanese specimens – and Dr Doleschall in flies and spiders, but with some spectacular local butterflies. He lodged with Mohnike, and enjoyed long conversations with the young Hungarian, Doleschall, blundering along gloriously in fluent though fearfully ungrammatical French. Following his established pattern, he sought out a more remote locality, and hired a boat to transport him to the north of the island – ‘with difficulty’, he grumbled, ‘for the Amboynese are dreadfully lazy’.16 He noted the wonderfully clear water in the harbour, and the richness of the marine life. In collecting terms, his great treasure here was the racquet-tailed kingfisher. He also found himself sharing his hut one day with a twelve-foot python, which had climbed up one of the posts and installed itself under the thatch within a yard of his head. His own boys would have nothing to do with ejecting it, but a local snake expert volunteered, and ‘proceeded to work in a businesslike manner’, with a long pole and a strong noose of rattan.17 The incident made a good illustration for The Malay Archipelago.

  The month drew to an end, and as he packed his boxes and waited for the steamer, he began another letter to Bates:

  To persons who have not thought much on the subject I fear my Paper ‘On the Succession of Species’ will not appear so clear as it does to you. That paper is of course merely the announcement of the theory, not its development. I have prepared the plans & written portions of an extensive work embracing the subject in all its bearings & endeavouring to prove what in the paper I have only indicated.

  Then, responding to Bates’s surprise that he had published so soon, he explained: ‘It was the promulgation of “Forbes’ theory” which led me to write & publish for I was annoyed to see such an ideal absurdity put forth when such a simple hypothesis will explain all the facts.’ He told Bates about the letter from Darwin, and his agreement with ‘almost every word’ of the paper; Darwin’s ‘Species and Varieties’ might save Wallace the trouble of writing the second part of his hypothesis, ‘by proving that there is no difference in nature between the origin of species & varieties, or he may give me trouble by arriving at another conclusion, but at all events his facts will be given for me to work upon.’ Tactfully, perhaps recalling Bates’s shared views, he added, ‘Your collections & my own will furnish most valuable materials to illustrate & prove the universal applicability of the hypothesis.’18 He did not complete this letter to Bates for another three weeks.

  On 8 January 1858, Wallace arrived at Ternate, a small island off the west coast of the large island of Gilolo (Halmahera). Through the influence of a wealthy Dutchman, Duivenboden – who owned half the town, a great many ships, and more than a hundred slaves – Wallace rented a spacious house. This had four rooms, a large hall, two verandas, a deep well, and a garden well planted with fruit trees. It was only five minutes from the beach and the market, and beyond in the other direction lay the slopes of the mountain, whose summit, four thousand or so feet, was perpetually wreathed with smoke – a still active volcano. Here Wallace could make a semi-permanent base, and he used this house as his principal residence for the next three years. Duivenboden traded in wild nutmeg from New Guinea, and Wallace booked his passage there on one of his schooners, which was due to sail in March. Meanwhile, the neighbouring island of Gilolo beckoned, ‘the most perfect Entomological “terra incognita” now to be found’, he told Bates in an addition to his letter. ‘In about a week I go for a month’s collecting there.’ He was also intrigued to meet the human inhabitants. R. C. Latham, in The Natural History of the Varieties of Man, had written about the possible origin of the Papuan race:

  The probable source, however, of the Papuan population must be sought for in the parts about Gilolo. Here the distinction between these islands which constitute the more eastern and northern portions of the Moluccas, and those which are considered to belong to New Guinea, must be drawn.

  Wallace was as interested in human races and varieties as he was in trogons and Heliconidae. Having secured his base in Ternate, he set off for Sedingole on Gilolo with two of Duivenboden’s sons, the brother of his Ternate landlord, a young Chinaman, and a Papuan crew. Sedingole, their destination, proved unsatisfactory for collecting, so Wallace hired a small boat, which deposited him, his two men and baggage at Dodinga, at the head of a deep bay opposite Ternate on the narrow central isthmus of the island. He persuaded its owner to vacate a small hut for a month’s rent of five guilders, installed himself and Ali, and on his very first walk obtained a few insects that were quite new to him. Things were looking good, when he fell ill with malaria.

  He remained at Dodinga for just over a month. His field journal for the period is sparse, with only three entries covering nine pages, describing his accommodation, the location of Dodinga, and the inhabitants:

  The natives of this large and almost unknown island were examined by me with much interest, as they would help to determine whether, independent of mixed races, there is any transition from the malay to the papuan type. I was soon satisfied by the first half-dozen I saw that they were of genuine papuan race, lighter in colour indeed than usual but still presenting the marked characters of the type in features and stature.… The stature alone marks them as distinct being decidedly above the average malay height, while the features are as palpably unmalay as those of the Europeans
or the negro.19

  Weakened by malaria, Wallace turned his attention to the one species he could observe without moving far from his hut, man.

  As often during times of enforced leisure, Wallace’s mind went into overdrive. His letters to Bates and Darwin show the general direction of his speculations. His Sarawak paper stated his clear understanding that species changed by natural succession and descent, one species ‘becoming changed either slowly or rapidly into another’. But the exact process of the change and the causes which led to it were unknown.

  The great difficulty was to understand how, if one species was gradually changed into another, there continued to be so many quite distinct species, so many which differed from their nearest allies by slight yet perfectly definite and constant characters.20

  This was the question that he turned over and over in his thoughts, as he lay down recovering from the succession of hot and cold fits, shivering and wrapped in blankets even though the thermometer was 88°; and on one of these days, the answer presented itself.

  One day something brought to my recollection Malthus’s ‘Principles of Population’, which I had read about twelve years before. I thought of his clear exposition of ‘the positive checks to increase’ – disease, accidents, war, and famine – which keep down the population of savage races to so much lower an average than that of more civilised peoples. It then occurred to me that these causes or their equivalents are continually acting in the case of animals also; and as animals usually breed much more rapidly than does mankind, the destruction every year from these causes must be enormous in order to keep down the numbers of each species, since they evidently do not increase regularly from year to year, as otherwise the world would long ago have been densely crowded with those that breed most quickly. Vaguely thinking over the enormous and constant destruction which this implied, it occurred to me to ask the question, Why do some die and some live? And the answer was clearly, that on the whole the best fitted live. From the effects of disease the most healthy escaped; from enemies, the strongest, the swiftest, or the most cunning; from famine, the best hunters or those with the best digestion; and so on. Then it suddenly flashed upon me that this self-acting process would necessarily improve the race, because in every generation the inferior would inevitably be killed off and the superior would remain – that is, the fittest would survive. Then at once I seemed to see the whole effect of this, that when changes of land and sea, or of climate, or of food supply, or of enemies occurred – and we know that such changes have always been taking place – in conjunction with the amount of individual variation that my experience as a collector had shown me to exist, then all the changes necessary for the adaptation of the species to the changing conditions would be brought about; and as great changes in the environment are always slow, there would be ample time for the change to be effected by the survival of the best fitted in every generation. In this way each part of an animal’s organisation could be modified exactly as required, and in the very process of this modification the unmodified would die out, and thus the definite characters and the clear isolation of each new species would be explained. The more I thought over it the more I became convinced that I had at length found the long-sought-for law of nature that solved the problem of the origin of species. For the next hour I thought over the deficiencies in the theories of Lamarck and of the author of the ‘Vestiges’, and I saw that my new theory supplemented these views and obviated every important difficulty.21

  Wallace wrote several accounts of this great moment of illumination, all of them retrospective. There is no reference to the event in his field journal, and in The Malay Archipelago he is silent about it, as he is about the Sarawak paper. In his version for the Darwin–Wallace Celebration in 1908, he expands the narrative: ‘Then there flashed upon me, as it had done twenty years before upon Darwin, the certainty …’21 By that time, he had been able to read the parallel episode in Darwin’s autobiography:

  In October 1838, that is, fifteen months after I had begun my systematic enquiry [on how species become modified… I happened to read for amusement Malthus on Population, and being well prepared to appreciate the struggle for existence which everywhere goes on from long-continued observation of the habits of animals and plants, it at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The result of this would be the formation of new species. Here then I had got at last a theory by which to work; but I was so anxious to avoid prejudice, that I determined not for some time to write even the briefest sketch of it. In June 1842 I first allowed myself the satisfaction of writing a very brief abstract of my theory in pencil in 35 pages; and this was enlarged during the summer of 1844 into one of 230 pages, which I had fairly copied out and still possess.23

  If the moment of inspiration, the flash of insight, was similar, the two men’s subsequent actions could not have been more contrasted. Wallace waited only for his malarial fit to subside to begin making notes for a paper. ‘The same evening I did this pretty fully, and on the two succeeding evenings wrote it out carefully in order to send it to Darwin by the next post, which would leave in a day or two.’24

  According to his field journal, he returned to Ternate on 1 March, although his paper, entitled ‘On the Tendency of Varieties to Depart Indefinitely from the Original Type’, is headed ‘Ternate, February, 1858’. The probable explanation for this inconsistency is that Wallace simply gave his main residence, and postal base, on his letters, rather than pedantically, or romantically, heading them ‘temporary hut near beach on almost unknown island’. The next mail boat was due on 9 March, so he had a few days to prepare his correspondence. He enclosed his letter to Bates with another to Bates’s brother Frederick: curiously, in view of the comments he had already written, he made no mention to Bates of the fact that he had by this time actually tackled the ‘development of the theory’. Instead, he wrote a letter to Darwin ‘in which I said that I hoped the idea would be as new to him as it was to me, and that it would supply the missing factor to explain the origin of species. I asked him, if he thought it sufficiently important, to show it to Sir Charles Lyell, who had thought so highly of my former paper’, the Sarawak one.25

  How did Wallace know about Lyell’s opinion? It can have been only from Darwin, who wrote about it to him on 22 December 1857, in a letter that must have arrived in Ternate while Wallace was marooned with fever at Dodinga, unless it came on the very same inter-island mail boat from Batavia that carried Wallace’s manuscript on the first leg of its journey to England. Darwin wrote:

  I am extremely glad to hear that you are attending to distribution in accordance with theoretical ideas. I am a firm believer, that without speculation there is no good & original observation. Few travellers have [at]tended to such points as you are now at work on; & indeed the whole subject of distribution of animals is dreadfully behind that of Plants.

  (Wallace had been telling Darwin about his ideas on the geographical distribution of animals, and indicating that he planned to spend another three or four years in the East.)

  You say that you have been somewhat surprised at no notice having been taken of your paper in the Annals: I cannot say that I am, for so very few naturalists care for anything beyond the mere description of species. But you must not suppose that your paper has not been attended to: two very good men, Sir C. Lyell, & Mr E. Blyth at Calcutta specially called my attention to it. Though agreeing with you on your conclusion[s] in that paper, I believe I go much further than you; but it is too long a subject to enter on my speculative notions. –

  Instead, he proceeds to discuss Wallace’s ‘doctrine of subsidence’, in regard to the former connection of islands with continents, and to answer his questions about the introduction of land-shells on oceanic islands by man’s agency. Then he responds to a more leading question:

  You ask whether I shall discuss ‘man’; I think I shall avoid the whole subject, as so surrounded with preju
dices, though I fully admit that it is the highest & most interesting problem for the naturalist. – My work, on which I have now been at work more or less for 20 years, will not fix or settle anything; but I hope it will aid by giving a large collection of facts with one definite end: I get on very slowly, partly from ill-health, partly from being a very slow worker. – I have got about half written; but I do not suppose I shall publish under a couple of years. I have now been three whole months on one chapter on Hybridism!26

  Much as Darwin had done with his first reading of the Sarawak paper, Wallace interpreted Darwin’s letter selectively, taking literally the sentence that the work he was engaged on would not ‘fix or settle anything’, and totally ignoring the implications of ‘I believe I go much further than you; but it is too long a subject to enter on my speculative notions’. Wallace, ‘the young man in a hurry’ as he later described himself, sealed up the fair copy of his new theory, and sent it to England for Darwin’s opinion.

  Wallace was eagerly preparing for his next expedition, bound for the mainland of New Guinea in Duivenboden’s schooner. He had high hopes of repeating his Aru success. He now had four servants to cater for, including Ali as head man, and he wasted valuable time searching out provisions and equipment. After his brilliant burst of theorising, it was back to the daily trials and frustrations of the European collector. He scoured the Ternate stores for beeswax, metal spoons, a penknife, wide-mouthed phials, even for a staple such as flour.

  8 In Search of Paradise Birds

  WALLACE AND HIS men sailed slowly east to New Guinea, at first almost becalmed, and in the later stages tacking against the wind. With every trip he made he was better prepared, and more self-sufficient: this time he took with him eighty pandanus-leaf mats, to protect his baggage and help roof his house when he arrived. New Guinea lay on the extreme edge of Dutch influence, terra incognita. As they neared the coast, Wallace gazed with intense interest on the rugged mountains, ‘retreating ridge behind ridge into the interior, where the foot of civilised man had never trod’ – the country of the cassowary and the tree kangaroo, ‘in whose dark forests lived the most extraordinary and the most beautiful of the feathered inhabitants of the earth’, the many different species of birds of paradise.1 Wallace waited impatiently for the wind to change and allow the Hester Helena to enter Dorey harbour, so that he might at last follow in the footsteps of the great French naturalist René Lesson, who had described birds of paradise on New Guinea in his Zoologie du voyage autour du monde in 1829, a voyage accomplished on board the corvette La Coquille.