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clapping of hands, but this distinction in the usage of the appeared westwards; while in New Zealand there are, words is by no means uniformly maintained. Among the according to Mr T. Kirk (Transactions of the New Zealand Romans acclamation was varied both in form and purpose. Institute, vol. ii. p. 131), no less than 250 species of At marriages it was usual for the spectators to shout Io naturalised plants, more than 100 of which spread widely Hymen, Hymenæe, or Talassio; a victorious army or general over the country, and often displace the native vegetation. was greeted with Io triumphe ; in the theatre acclamation Among animals, the European rat, goat, and pig, are was called for at the close of the play by the last actor, naturalised in New Zealand, where they multiply to such who said, Plaudite; in the senate opinions were expressed an extent as to injure and probably exterminate many and votes passed by acclamation in such forms as Omnes, native productions. In neither of these cases is there omnes, Æquum est, Justum est, &c; and the praises of the any indication that acclimatisation was necessary or ever emperor were celebrated in certain pre-arranged sentences, took place. which seem to have been chanted by the whole body of On the other hand, the fact that an animal or plant senators. The acclamations which authors and poets who cannot be naturalised is no proof that it is not acclimatised. recited their works in public received were at first spon- It has been shown by Mr Darwin that, in the case of most taneous and genuine, but in time became very largely animals and plants in a state of nature, the competition of mercenary, it being customary for men of fortune who other organisms is a far more efficient agency in limiting affected literary tastes to keep applauders in their service their distribution than the mere influence of climate. We and lend them to their friends. When Nero performed in have a proof of this in the fact that so few, comparatively, the theatre his praises were chanted, at a given signal, by of our perfectly hardy garden plants ever run wild; and five thousand soldiers, who were called Augustals. The even the most persevering attempts to naturalise them whole was conducted by a music-master, mesochorus or usually fail. Alphonse de Candolle (Géographie Botanique, pausarius. It was this case of Nero which, occurring to p. 798) informs us that several botanists of Paris, Geneva, the recollection of the French poet Dorat, may be said to and especially of Montpellier, have sown the seeds of many have originated the well-known Paris claque. Buying up hundreds of species of exotic hardy plants, in what appeared a number of the tickets for a performance of one of his to be the most favourable situations, but that in hardly plays, he distributed them gratuitously to those who pro a single case has any one of them become naturalised. mised to express approbation. From that time the claque, Attempts have also been made to naturalise continental or organised body of professional applauders, has been a insects in this country, in places where the proper foodrecognised institution in connection with the theatres of plants abound and the conditions seem generally favourParis. In the early ages of the Christian church it was by able, but in no case do they seem to have succeeded. no means uncommon for an audience to express their appro- Even a plant like the potato, so largely cultivated and so bation of a favourite preacher during the course of his perfectly hardy, has not established itself in a wild state sermon. Chrysostom especially was very frequently inter- in any part of Europe. rupted both by applause and by acclamations. In eccle Different Degrees of Climatal Adaptation in Animals and siastical councils vote by acclamation is very common, the Plants.—Plants differ greatly from animals in the closeness question being usually put in the form, placet or non placet. of their adaptation to meteorological conditions. Not only This differs from the acclamation with which in other will most tropical plants refuse to live in a temperate assemblies a motion is said to be carried, when, no amend climate, but many species are seriously injured by removal ment being proposed, approval is expressed by shouting a few degrees of latitude beyond their natural limits. This such words as Aye or Agreed.
is probably due to the fact, established by the experiments ACCLIMATISATION is the process of adaptation by of M. Becquerel, that plants possess no proper temperature, which animals and plants are gradually rendered capable but are wholly dependent on that of the surrounding of surviving and flourishing in countries remote from their medium. original habitats, or under meteorological conditions dif Animals, especially the higher forms, are much less ferent from those which they have usually to endure, and sensitive to change of temperature, as shown by the extenwhich are at first injurious to them.
sive range from north to south of many species. Thus, The subject of acclimatisation is very little understood, the tiger ranges from the equator to northern Asia as far and some writers have even denied that it can ever take as the river Amour, and to the isothermal of 32° Fahr. The place. It is often confounded with domestication or with mountain sparrow (Passer montana) is abundant in Java naturalisation ; but these are both very different pheno- and Singapore in a uniform equatorial climate, and also
A domesticated animal or a cultivated plant need not inhabits this country and a considerable portion of northern necessarily be acclimatised ; that is, it need not be capable Europe. It is true that most terrestrial animals are of enduring the severity of the seasons without protection. restricted to countries not possessing a great range of The canary bird is domesticated but not acclimatised, and temperature or very diversified climates, but there is reason many of our most extensively cultivated plants are in the to believe that this is due to quite a different set of causes, same category. A naturalised animal or plant, on the such as the presence of enemies or deficiency of appropriate other hand, must be able to withstand all the vicissitudes food. When supplied with food and partially protected of the seasons in its new home, and it may therefore be from enemies, they often show a wonderful capacity of thought that it must have become acclimatised. But in enduring climates very different from that in which they many, perhaps most cases of naturalisation, there is no originally flourished. Thus, the horse and the domestic evidence of a gradual adaptation to new conditions which fowl, both natives of very warm countries, flourish without were at first injurious, and this is essential to the idea of special protection in almost every inhabited portion of the acclimatisation. On the contrary, many species, in a new globe. The parrot tribe form one of the most pre-eminently country and under somewhat different climatic conditions, tropical groups of birds, only a few species extending into seem to find a more congenial abode than in their native land, the warmer temperate regions; yet even the most excluand at once flourish and increase in it to such an extent as sively tropical genera are by no means delicate birds as often to exterminate the indigenous inhabitants. Thus Agassiz regards climate. In the Annals and Magazine of Natural (in his work on Lake Superior) tells us that the road-side History for 1868 (p. 381) is a most interesting account, by weeds of the north-eastern United States, to the number of Mr Charles Buxton, M.P., of the naturalisation of parrots 130 species, are all European, the native weeds having dis- | at Northreps Hall. Norfolk. A considerable number of
African and Amazonian parrots, Bengal parroquets, four , and some animals are, more or less closely, adapted to species of white and rose crested cockatoos, and two species climates similar to those of their native habitats. In order of crimson lories, have been at large for many years. to domesticate or naturalise the former class in countries Several of these birds have bred, and they almost all live not extremely differing from that from which the species in the woods the whole year through, refusing to take was brought, it will not be necessary to acclimatise, in shelter in a house constructed for their use. Even when the strict sense of the word. In the case of the latter the thermometer fell 6° below zero, all appeared in good class, however, acclimatisation is a necessary preliminary spirits and vigorous health. Some of these birds have to naturalisation, and in many cases to useful domesticalived thus exposed for nearly twenty years, enduring our tion, and we have therefore to inquire whether it is cold easterly winds, rain, hail, and snow, all through the possible. winter,-a marvellous contrast to the equable equatorial Acclimatisation by Individual Adaptation. It is evitemperature (hardly ever less than 70°) which many of them dent that acclimatisation may occur (if it occurs at all) in had been accustomed to for the first year or years of their two ways, either by modifying the constitution of the existence.
individual submitted to the new conditions, or by the Mr Jenner Weir records somewhat similar facts in the production of offspring which may be better adapted to Zoologist for 1865 (p. 9411). He keeps many small birds those conditions than their parents. The alteration of the in an open aviary in his garden at Blackheath, and among constitution of individuals in this direction is not easy to these are the Java rice bird (Padda oryzivora), two West detect, and its possibility has been denied by many writers. African weaver birds (Hyphantornis textor and Euplectes Mr Darwin believes, however, that there are indications sanguinirostris), and the blue bird of the southern United that it occasionally occurs in plants, where it can be best States (Spiza cyanea). These denizens of the tropics prove observed, owing to the circumstance that so many plants quite as hardy as our native birds, having lived during are propagated by cuttings or buds, which really continue the severest winters without the slightest protection the existence of the same individual almost indefinitely. against the cold, even when their drinking water had to be He adduces the example of vines taken to the West Indies repeatedly melted.
from Madeira, which have been found to succeed better Hardly any group of Mammalia is more exclusively than those taken directly from France. But in most cases tropical than the Quadrumana, yet there is reason to believe habit, however prolonged, appears to have little effect on that, if other conditions are favourable, some of them can the constitution of the individual, and the fact has no withstand a considerable degree of cold. The Semnopithecus doubt led to the opinion that acclimatisation is impossible. schistaceus was found by Captain Hutton at an elevation of There is indeed little or no evidence to show that any 11,000 feet in the Himalayas, leaping actively among fir- animal to which a new climate is at first prejudicial can trees whose branches were laden with snow-wreaths. In be so acclimatised by habit that, after subjection to it for a Abyssinia a troop of dog-faced baboons were observed by few or many seasons, it may live as healthily and with as Mr Blandford at 9000 feet above the sea. We may there- little care as in its native country; yet we may, on general fore conclude that the restriction of the monkey tribe to principles, believe that under proper conditions such accliwarm latitudes is probably determined by other causes than matisation would take place. In his Principles of Biology temperature alone.
(chap. v.), Mr Herbert Spencer has shown that every organ Similar indications are given by the fact of closely allied and every function of living beings undergoes modification species inhabiting very extreme climates. The recently to a limited extent under the stimulus of any new conextinct Siberian mammoth and woolly rhinoceros were ditions, and that the modification is almost always such as closely allied to species now inhabiting tropical regions to produce an adaptation to those conditions. We may feel exclusively. Wolves and foxes are found alike in the pretty sure, therefore, that if robust and healthy individuals coldest and hottest parts of the earth, as are closely allied are chosen for the experiment, and if the change they are species of falcons, owls, sparrows, and numerous genera of subjected to is not too great, a real individual adaptation waders and aquatic birds.
to the new conditions—that is, a more or less complete A consideration of these and many analogous facts might acclimatisation—will be brought about. If now animals induce us to suppose that, among the higher animals at thus modified are bred from, we know that their descendants least, there is little constitutional adaptation to climate, will inherit the modification. They will thus start more and that in their case acclimatisation is not required. But favourably, and being subject to the influence of the same there are numerous examples of domestic animals which or a slightly more extreme climate during their whole lives, show that such adaptation does exist in other cases. The the acclimatisation will be carried a step further; and yak of Thibet cannot long survive in the plains of India, there seems no reason to doubt that, by this process alone, or even on the hills below a certain altitude; and that this if cautiously and patiently carried out, most animals which is due to climate, and not to the increased density of the breed freely in confinement could in time be acclimatised atmosphere, is shown by the fact that the same animal in almost any inhabited country. There is, however, a appears to thrive well in Europe, and even breeds there much more potent agent, which renders the process of readily. The Newfoundland dog will not live in India, and adaptation almost a certainty. the Spanish breed of fowls in this country suffer more Acclimatisation by Variation.—A mass of evidence exists from frost than most others. When we get lower in the showing that variations of every conceivable kind occur scale the adaptation is often more marked. Snakes, which among the offspring of all plants and animals, and that, in are so abundant in warm countries, diminish rapidly as particular, constitutional variations are by no means unwe go north, and wholly cease at lat. 62°. Most insects are
Among cultivated plants, for example, hardier also very susceptible to cold, and seem to be adapted to and more tender varieties often arise. The following cases very narrow limits of temperature.
are given by Mr Darwin :-Among the numerous fruit-trees From the foregoing facts and observations we may con raised in North America, some are well adapted to the -lude, firstly, that some plants and many animals are not climate of the Northern States and Canada, while others constitutionally adapted to the climate of their native only succeed well in the Southern States. Adaptation of country only, but are capable of enduring and flourishing this kind is sometimes very close, so that, for example, few under a more or less extensive range of temperature and English varieties of wheat will thrive in Scotland. Seedother climatic conditions; and, secondly, that most plants wheat from India produced a miserable crop when planted
by the Rev. M. J. Berkeley on land which would have | Himalayan conifers and rhododendrons, raised in this produced a good crop of English wheat. Conversely, country from seed gathered at different altitudes. French wheat taken to the West Indies produced only Among animals exactly analogous facts occur. M. Roulin barren spikes, while native wheat by its side yielded an states that when geese were first introduced into Bogota enormous harvest. Tobacco in Sweden, raised from home they laid few eggs at long intervals, and few of the young grown seed, ripens its seeds a month earlier than plants survived. By degrees the fecundity improved, and in grown from foreign seed. In Italy, as long as orange about twenty years became equal to what it is in Europe. trees were propagated by grafts, they were tender ; but the same author tells us that, according to Garcilaso, after many of the trees were destroyed by the severe frosts when fowls were first introduced into Peru they were not of 1709 and 1763, plants were raised from seed, and these fertile, whereas now they are as much so as in Europe. were found to be hardier and more productive than the Mr Darwin adduces the following examples. Merino sheep former kinds. Where plants are raised from seed in large bred at the Cape of Good Hope have been found far better quantities, varieties always occur differing in constitution, adapted for India than those imported from England; and as well as others differing in form or colour; but the former while the Chinese variety of the Ailanthus silk-moth is cannot be perceived by us unless marked out by their quite hardy, the variety found in Bengal will only flourish behaviour under exceptional conditions, as in the following in warm latitudes. Mr Darwin also calls attention to the cases. After the severe winter of 1860-61, it was observed circumstance that writers of agricultural works generally that in a large bed of araucarias some plants stood quite recommend that animals should be removed from one unhurt among numbers killed around them. In Mr Darwin's district to another as little as possible. This advice occurs garden two rows of scarlet runners were entirely killed by even in classical and Chinese agricultural books as well frost, except three plants, which had not even the tips of as in those of our own day, and proves that the close their leaves browned. A very excellent example is to be adaptation of each variety or breed to the country in which found in Chinese history, according to M. Huc, who, in it originated has always been recognised. his L'Empire Chinois (tom. ï. p. 359), gives the following Constitutional Adaptation often accompanied by External extract from the Memoirs of the Emperor Khang :-“On Modification.—Although in some cases no perceptible alterathe 1st day of the 6th moon I was walking in some fields. tion of form or structure occurs when constitutional adaptawhere rice had been sown to be ready for the harvest in tion to climate has taken place, in others it is very marked. the 9th moon. I observed by chance a stalk of rice Mr Darwin has collected a large number of cases in his Animals which was already in ear. It was higher than all the rest, and Plants under Domestication (vol. ii. p. 277), of which the and was ripe enough to be gathered. I ordered it to be following are a few of the most remarkable. Dr Falconer brought to me. The grain was very fine and well grown, observed that several trees, natives of cooler climates, which gave me the idea to keep it for a trial, and see if the assumed a pyramidal or fastigiate form when grown in the following year it would preserve its precocity. It did so. plains of India ; cabbages rarely produce heads in hot All the stalks which came from it showed ear before climates ; the quality of the wood, the medicinal products, the usual time, and were ripe in the 6th moon. Each
the odour and colour of the flowers, all change in many has multiplied the produce of the preceding, and for thirty cases when plants of one country are grown in another. years it is this rice which has been served at my table. The One of the most curious observations is that of Mr Meehan, grain is elongate, and of a reddish colour, but it has a sweet who “compared twenty-nine kinds of American trees smell and very pleasant taste. It is called Yu-mi, Imperial belonging to various orders, with their nearest European rice, because it was first cultivated in my gardens. It is allies, all grown in close proximity in the same garden, and the only sort which can ripen north of the great wall, under as nearly as possible the same conditions. In the where the winter ends late and begins very early; but in American species Mr Meehan finds, with the rarest excepthe southern provinces, where the climate is milder and the tions, that the leaves fall earlier in the season, and assume land more fertile, two harvests a year may be easily ob- before falling a brighter tint; that they are less deeply tained, and it is for me a sweet reflection to have procured toothed or serrated; that the buds are smaller; that the this advantage for my people.” M. Huc adds his testimony trees are more diffuse in growth, and have fewer branchlets; that this kind of rice fourishes in Mandtchuria, where no and, lastly, that the seeds are smaller ;-all in comparison other will grow.
We have here, therefore, a perfect with the European species.” Mr Darwin concludes that example of acclimatisation by means of a spontaneous con there is no way of accounting for these uniform differences stitutional variation,
in the two series of trees than by the long-continued action That this kind of adaptation may be carried on step by of the different climates of the two continents. step to more and more extreme climates is illustrated by In animals equally remarkable changes occur. In the following examples. Sweet-peas raised in Calcutta Angora, not only goats, but shepherd-dogs and cats, have from seed imported from England rarely blossom, and never fine fleecy hair; the wool of sheep changes its character in yield seed; plants from French seed flower better, but are the West Indies in three generations; M. Costa states still sterile; but those raised from Darjeeling seed (originally that young oysters, taken from the coast of England, imported from England) both flower and seed profusely. The and placed in the Mediterranean, at once altered their peach is believed to have been tender, and to have ripened manner of growth and formed prominent diverging rays, its fruit with difficulty, when first introduced into Greece; so like those on the shells of the proper Mediterranean that (as Darwin observes) in travelling northward during oyster. two thousand years it must have become much hardier. In his Contributions to the Theory of Natural Selection Dr Hooker ascertained the average vertical range of (p. 167), Mr Wallace has recorded cases of simultaneous flowering plants in the Himalayas to be 4000 feet, while in variation among insects, apparently due to climate or other some cases it extended to 8000 feet. The same species can strictly local causes. He finds that the butterflies of the thus endure a great difference of temperature; but the family Papilionidæ, and some others, become similarly important fact is, that the individuals have become accli- modified in different islands and groups of islands. Thus, matised to the altitude at which they grow, so that seeds the species inhabiting Sumatra, Java, and Borneo, are gathered near the upper limit of the range of a species will almost always much smaller than the closely allied species be more hardy than those gathered near the lower limit. of Celebes and the Moluccas; the species or varieties of This was proved by Dr Hooker to be the case with the small island of Amboyna are larger than the same
species or closely allied forms inhabiting the surrounding the influence of natural agencies, which render existence islands; the species fcund in Celebes possess a peculiar impossible for those that vary in any other direction, or form of wing, quite distinct from that of the same or by the action of the judicious breeder, who carefully selects closely allied species of adjacent islands; and, lastly, favourable variations to be the parents of his future stock; numerous species which have tailed wings in India and the and in either case the rejected variations may far outnumber western islands of the Archipelago, gradually lose the tail those which are preserved. as we proceed eastward to New Guinea and the Pacific. Evidence has been adduced by Mr Darwin to show that
Many of these curious modifications may, it is true, be the tendency to vary is itself hereditary; so that, so far due to other causes than climate only, but they serve to from variations coming to an end, as some persons imagine, show how powerfully and mysteriously local conditions the more extensively variation has occurred in any species affect the form and structure of both plants and animals; | in the past, the more likely it is to occur in the future. and they render it probable that changes of constitution There is also reason to believe that individuals which have are also continually produced, although we have, in the varied largely from their parents in a special direction will majority of cases, no means of detecting them. It is also have a greater tendency to produce offspring varying in impossible to determine how far the effects described are that direction than in any other; so that the facilities for produced by spontaneous favourable variations or by the adaptation, that is, for the production and increase of direct action of local conditions; but it is probable that in favourable variations in certain definite directions, are far every case both causes are concerned, although in constantly greater than the facilities for locomotion in one direction in varying proportions.
the hypothetical illustration just given. The Influence of Heredity.---Adaptation by variation Selection and Survival of the Fittest as Agents in Naturawould, however, be a slow and uncertain process, and might lisation.—We may now take it as an established fact, that for considerable periods of time cease to act, did not heredity varieties of animals and plants occur, both in domesticity and come into play. This is the tendency of every organism to in a state of nature, which are better or worse adapted to produce its like, or more exactly, to produce a set of newforms special climates. There is no positive evidence that the varying slightly from it in many directions—a group of which influence of new climatal conditions on the parents has any the parent form is the centre. If now one of the most ex- tendency to produce variations in the offspring better adapted treme of these variations is taken, it is found to become the to such conditions, although some of the facts mentioned centre of a new set of variations; and by continually taking in the preceding sections render it probable that such may the extreme in the same direction, an increasing variation in
be the case.
Neither does it appear that this class of that direction can be effected, until checked by becoming variations are very frequent. It is, however, certain that so great that it interferes with the healthy action of the whenever any animal or plant is largely propagated conorganism, or is in any other way prejudicial. It is also stitutional variations will arise, and some of these will be found that acquired constitutional peculiarities are equally better adapted than others to the climatal and other hereditary; so that by a combination of those two modes of conditions of the locality. In a state of nature, every variation any desired adaptation may be effected with recurring severe winter or otherwise unfavourable season, greater rapidity. The manner in which the form or weeds out those individuals of tender constitution or constitution of an organism can be made to change con- imperfect structure which may have got on very well during tinuously in one direction, by means of variations which favourable years, and it is thus that the adaptation of the are indefinite and in all directions, is often misunderstood. species to the climate in which it has to exist is kept up. It may perhaps be illustrated by showing how a tree or Under domestication the same thing occurs by what Mr grove of trees might, by natural causes, be caused to travel Darwin has termed “unconscious selection." Each cultiduring successive generations in a definite course. The vator seeks out the kinds of plants best suited to his soil tree has branches radiating out from its stem to perhaps and climate, and rejects those which are tender or otherwise twenty feet on every side. Seeds are produced on the unsuitable. The farmer breeds from such of his stock as extremities of all these branches, drop to the ground, and he finds to thrive best with him, and gets rid of those produce seedlings, which, if untouched, would form a ring which suffer from cold, damp, or disease. A more or less of young trees around the parent. But cattle crop off close adaptation to local conditions is thus brought about, every seedling as soon as it rises above the ground, and and breeds or races are produced which are sometimes none can ever arrive at maturity. If, however, one side is liable to deterioration on removal even to a short distance protected from the cattle, young trees will grow up on that in the same country, as in numerous cases quoted by Mr side only. This protection may exist in the case of a grove Darwin (Animals and Plants under Domestication, vol. Ü of trees which we may suppose to occupy the whole space
p. 273). between two deep ravines, the cattle existing on the lower The Method of Acclimatisation. Taking into consideraside of the wood only. In this case young trees would tion the foregoing facts and illustrations, it may be conreach maturity on the upper side of the wood, while on the sidered as proved—lst, That habit has little (though it lower side the trees would successively die, fall, and rot appears to have some) definite effect in adapting the away, no young ones taking their place. If this state of constitution of animals to a new climate; but that it has a things continued unchanged for some centuries, the wood decided, though still slight, influence in plants when, by might march regularly up the side of the mountain till it the process of propagation by buds, shoots, or grafts, the occupied a position many miles away from where it once individual can be kept under its influence for long periods ; stood; and this would have taken place, not because more 2d, That the offspring of both plants and animals vary seed was produced on one side than the other (there might in their constitutional adaptation to climate, and that even be very much less), nor because soil or climate were this adaptation may be kept up and increased by means better on the upper side (they might be worse), nor because of heredity; and, 3d, That great and sudden changes any intelligent being chose which trees should be allowed of climate often check reproduction even when the health to live and which should be destroyed;—but simply because, of the individuals does not appear to suffer. In order, for a series of generations, the conditions permitted the therefore, to have the best chance of acclimatising any existence of young trees on one side, and wholly prevented animal or plant in a climate very dissimilar from that of it on the other. Just in an analogous way animals or its native country, and in which it has been proved that plants are caused to vary in definite directions, either by the species in question cannot live and maintain itself
without acclimatisation, we must adopt some such plan | have the same phenomenon in single varieties of man, such as as the following :
the American, which inhabits alike the frozen wastes of 1. We must transport as large a number as possible of Hudson's Bay and Terra del Fuego, and the hottest regions adult healthy individuals to some intermediate station, of the tropics,—the low equatorial valleys and the lofty and increase them as much as possible for some years. plateaux of the Andes. No doubt a sudden transference Favourable variations of constitution will soon show them to an extreme climate is often prejudicial to man, as it is selves, and these should be carefully selected to breed from, to most animals and plants; but there is every reason to the tender and unhealthy individuals being rigidly elimi- believe that, if the migration occurs step by step, man can nated.
be acclimatised to almost any part of the earth's surface 2. As soon as the stock has been kept a sufficient time in comparatively few generations. Some eminent writers to pass through all the ordinary extremes of climate, a have denied this. Sir Ranald Martin, from a consideration number of the hardiest may be removed to the more remote of the effects of the climate of India on Europeans and station, and the same process gone through, giving protection their offspring, believes that there is no such thing as if necessary while the stock is being increased, but as soon acclimatisation. Dr Hunt, in a report to the British as a large number of healthy individuals are produced, sub- Association in 1861, argues that “time is no agent," and jecting them to all the vicissitudes of the climate.
-“ if there is no sign of acclimatisation in one generation, It can hardly be doubted that in most cases this plan would there is no such process.” But he entirely ignores the succeed. It has been recommended by Mr Darwin, and at effect of favourable variations, as well as the direct inone of the early meetings of the Société Zoologique d’Acclim- fluence of climate acting on the organisation from infancy. atisation, at Paris, M. Geoffroy St Hilaire insisted that it was Professor Waitz, in his Introduction to Anthropology, the only method by which acclimatisation was possible. adduces many examples of the comparatively rapid conBut in looking through the long series of volumes of Reports stitutional adaptation of man to new climatic conditions. published by this Society, there is no sign that any systematic Negroes, for example, who have been for three or four attempt at acclimatisation has even once been made. A generations acclimatised in North America, on returning tu number of foreign animals have been introduced, and more or Africa become subject to the same local diseases as other less domesticated, and some useful exotics have been culti-unacclimatised individuals. He well remarks, that the vated for the purpose of testing their applicability to French debility and sickening of Europeans in many tropica] agriculture or horticulture; but neither in the case of countries are wrongly ascribed to the climate, but are animals nor of plants has there been any systematic effort rather the consequences of indolence, sensual gratification, to modify the constitution of the species, by breeding largely and an irregular mode of life. Thus the English, who and selecting the favourable variations that appeared. cannot give up animal food and spirituous liquors, are less
Take the case of the Eucalyptus globulus as an example. able to sustain the heat of the tropics than the more sober This is a Tasmanian gum-tree of very rapid growth and Spaniards and Portuguese. The excessive mortality of great beanty, which will thrive in the extreme south of European troops in India, and the delicacy of the children France. In the Bulletin of the Society a large number of of European parents, do not affect the real question of attempts to introduce this tree into general cultivation in acclimatisation under proper conditions. They only show other parts of France are recorded in detail, with the failure that acclimatisation is in most cases necessary, not that it of almost all of them. But no precautions such as those cannot take place. The best examples of partial or comabove indicated appear to have been taken in any of these plete acclimatisation are to be found where European races experiments; and we have no intimation that either the have permanently settled in the tropics, and have maintained Society or any of its members are making systematic themselves for several generations. There are, however, efforts to acclimatise the tree. The first step would be, to two sources of inaccuracy to be guarded against, and these obtain seed from healthy trees growing in the coldest are made the most of by the writers above referred to, and climate and at the greatest altitude in its native country, are supposed altogether to invalidate results which are sowing these very largely, and in a variety of soils and otherwise opposed to their views. In the first place, we situations, in a part of France where the climate is some have the possibility of a mixture of native blood having what but not much more extreme. It is almost a certainty occurred; in the second, there have almost always been a that a number of trees would be found to be quite hardy. succession of immigrants from the parent country, who As soon as these produced seed, it should be sown in continually intermingle with the families of the early the same district and farther north in a climate a little settlers. It is maintained that one or other of these more severe. After an exceptionally cold season, seed mixtures is absolutely necessary to enable Europeans to should be collected from the trees that suffered least, and continue long to flourish in the tropics. should be sown in various districts all over France. By There are, however, certain cases in which the sources such a process there can be hardly any doubt that the tree of error above mentioned are reduced to a minimum, and would be thoroughly acclimatised in any part of France, cannot seriously affect the results; such as those of the and in many other countries of central Europe ; and more Jews, the Dutch at the Cape of Good Hope and in the good would be effected by one well-directed effort of this Moluccas, and the Spaniards in South America. kind than by hundreds of experiments with individual The Jews are a good example of acclimatisation, because animals and plants, which only serve to show us which are they have been established for many centuries in climates the species that do not require to be acclimatised.
very different from that of their native land; they keep Acclimatisation of Man.-On this subject we have, un themselves almost wholly free from intermixture with the fortunately, very little direct or accurate information. The people around them; and they are often so populous in a general laws of heredity and variation have been proved to country that the intermixture with Jewish immigrants from apply to man as well as to animals and plants; and nume- other lands cannot seriously affect the local purity of the rous facts in the distribution of races show that man must, in race. They have, for instance, attained a population of near remote ages at least, have been capable of constitutional | two millions in such severe climates as Poland and Russia; adaptation to climate. If the human race constitutes a single and according to Mr Brace (Races of the Old World, p. 185), species, then the mere fact that man now inhabits every “their increase in Sweden is said to be greater than that region, and is in each case constitutionally adapted to the of the Christian population; in the towns of Algeria they climate, proves that acclimatisation has occurred. But we are the only race able to maintain its numbers; and in