The Leighton bequest (Lord Leighton, P.R.A.), received from Mrs Orr and Mrs Matthews in memory of their brother, the income from which, about L. 300, is expended on the decoration of public places and buildings.

The literature concerning the Royal Academy consists chiefly of pamphlets and articles of more or less ephemeral value. More serious works are: William Sandby, The History of the Royal Academy of Arts (London, 1862) (withdrawn from circulation on a question of copyright); Report from the Select Committee on Arts and their Connexion with Manufactures, with the Minutes of Evidence and Appendix (London, 1836 ); Report of the Royal Commission on the Royal Academy, with Minutes of Evidence and Appendix (London, 1863); Martin Archer Shee, The Life of Sir M. A. Shee, P.R.A. (London, 1860); C. R. Leslie, R.A., and Tom Taylor, Life and Times of Sir Joshua Reynolds, P.R.A. (London, 1865); J. E. Hodgson, R.A. (the late), and Fred. A. Eaton, Sec. R.A., "The Royal Academy in the Last Century,'' Art Journal, 1889-1901. But the chief sources of information on the subject are the minute-books of the council and of the general assembly, and the annual reports, which, however, only date from 1859. (F. A. E.)

ACADIAN, in geology, the name given by Sir J. W. Dawson in 1867 to a series of black, red and green shales and slates, with dark grey limestones, which are well developed at St John, New Brunswick; Avalon in E. Newfoundland, and Braintree in E. Massachusetts. These rocks are of Middle Cambrian age and possess a Paradoxides fauna. They have been correlated with limestone beds in Tennessee, Alabama, central Nevada and British Columbia (St Stephen).

See CAMBRIAN SYSTEM; also C. D. Walcott, Bull. U.S. Geol. Survey, No. 81, 1891; and Sir J. W. Dawson, Acadian Geology, 1st ed. 1855, 3rd ed. 1878.

ACADIE, or ACADIA, a name given by the French in 1603 to that part of the mainland of North America lying between the latitudes 40 deg. and 46 deg. . In the treaty of Utrecht (1713) the words used in transferring the French possessions to Britain were "Nova Scotia or Acadia.'' See NOVA SCOTIA for the limits included at that date under the term.

ACAMTHOCEPHALA, a compact group of cylindrical, parasitic worms, with no near allies in the animal kingdom. Its members are quite devoid of any mouth or alimentary canal, but have a well-developed body cavity into which the eggs are dehisced and which communicates with the exterior by



From Cambridge Natural History, vol. ii., "Worms, &c.,'' by permission of Macmillan & Co., Ltd.

Fig. 1. A, Five specimens of Echinorhynchus acus, Rud., attached to a piece of intestinal wall, X 4.

B, The proboscis of one still more highly magnified.

means of an oviduct. The size of the animals varies greatly, from forms a few millimetres in length to Gigantorhynchus gigas, which measures from 10 to 65 cms. The adults live in great numbers in the alimentary canal of some vertebrate, usually fish, the larvae are as a rule encysted in the body cavity of some invertebrate, most often an insect or crustacean, more rarely a small fish. The body is divisible into a proboscis and a trunk with sometimes an intervening neck region. The proboscis bears rings of recurved hooks arranged in horizontal rows, and it is by means of these hooks that the animal attaches itself to the tissues of its host. The hooks may be of two or three shapes. Like the body, the proboscis is hollow, and its cavity is separated from the body cavity by a septum or proboscis sheath. Traversing the cavity of the proboscis are muscle-strands inserted into the tip of the proboscis at one end and into the septum at the other. Their contraction causes the proboscis to be invaginated into its cavity (fig. 2). But the whole proboscis apparatus can also be, at least partially, withdrawn into the body cavity, and this is effected by two retractor muscles which run from the posterior aspect of the septum to the body wall (fig. 3).

The skin is peculiar. Externally is a thin cuticle; this covers the epidermis, which consists of a syncytium with no cell limits. The syncytium is traversed by a series of branching tubules containing fluid and is controlled by a few wandering, amoeboid nuclei (fig. 2). Inside the syncytium is a not very regular layer of circular muscle fibres, and within this again some rather scattered longitudinal fibres; there is no endothelium. In their minute structure the muscular fibres resemble those of Nematodes. Except for the absence of the longitudinal fibres the skin of the proboscis resembles that of the body, but the fluid-containing tubules of the latter are shut off from those of the body. The canals of the proboscis open ultimately into a circular vessel which runs round its base. From the circular canal two sac-like diverticula called the

From Cambridge Natural History, vol. ii., "Worms, &c.,'' by permission of Macmillan & Co., Ltd.

FIG. 2.—A longitudinal section through the anterior end of Echinorhynchus haeruca, Rud. (from

a, The proboscis not fully expanded. b, Proboscis-sheath. c, Retractor muscles of the proboscis. d, Cerebral ganglion. e, Retinaculum enclosing a nerve f, One of the retractors of the sheath. g, A lemniscus. h, One of the spaces in the sub-cuticular tissue. i, Longitudinal muscular layer. j, Circular muscular laver. k, Line of division between the sub-cuticular tissue of the trunk and that of the proboscis with the lemnisci.

"lemnisci'' depend into the cavity of the body (fig. 2). Each consists of a prolongation of the syncytial material of the proboscis skin, penetrated by canals and sheathed with a scanty muscular coat. They seem to act as reservoirs into which the fluid of the tense, extended proboscis can withdraw when it is retracted, and from which the fluid can be driven out when it is wished to expand the proboscis.

There are no alimentary canal or specialized organs for circulation or for respiration. Food is imbibed through the skin from the digestive juices of the host in which the Acanthocephala live.

J. Kaiser has described as kidneys two organs something like minute shrubs situated dorsally to the generative ducts into which they open. At the end of each twig is a membrane pierced by pores, and a number of cilia depend into the lumen of the tube; these cilia maintain a constant motion.

The central ganglion of the nervous system lies in the proboscis sheath or septum. It supplies the proboscis with nerves and gives off behind two stout trunks which supply the body (fig. 2). Each of these trunks is surrounded by muscles, and the complex retains the old name of "retinaculum.'' In the male at least there is also a genital ganglion. Some scattered papillae may possibly be sense-organs.

The Acanthocephala are dioecious. There is a "stay'' called the "ligament'' which runs from the hinder end of the proboscis sheath to the posterior end of the body. In this the two testes lie (fig. 3). Each opens in a vas deferens which bears three diverticula or vesiculae seminales, and three pairs of cement glands also are found which pour their secretions through a duct into the vasa deferentia. The latter unite and end in a penis which opens posteriorly.



Fig. 3.—-An optical section through a male Neorhynchus clavaeceps, Zed. (from Hamann).

a, Proboscis. b, Proboscis sheath. c, Retractor of the proboscis. d, Cerebral ganglion. f, f, Petractors of the proboscis sheath. g, g, Lemnisci, each with two giant nuclei. h, Space in sub-cuticular layer of the skin. l, Ligament. m, m, Testes. o, Glands on vas deferens. p, Giant nucleus in skin. q, Opening of vas deferens.

The ovaries arise like the testes as rounded bodies in the ligament. From these masses of ova dehisce into the body cavity and float in its fluid. Here the eggs are fertilized and here they segment so that the young embryos are formed within their mother's body. The embryos escape into the uterus through the "bell,'' a funnel like opening continuous with the uterus. Just at the junction of the "bell'' and the uterus there is a second small opening situated dorsally. The "bell'' swallows the matured embryos and passes them on into the uterus, and thus out of the body via the oviduct, which opens at one end into the uterus and at the other on to the exterior at the posterior end of the body. But should the "bell'' swallow any of the ova, or even one of the younger embryos, these are passed back into the body cavity through the second and dorsal opening.

The embryo thus passes from the body of the female into the alimentary canal of the host and leaves this with the faeces. It is then, if lucky, eaten by some crustacean, or insect, more rarely by a fish. In the stomach it casts its membranes and becomes mobile, bores through the stomach walls and encysts usually in the cavity of its first and invertebrate host. By this time the embryo has all the organs of the adult perfected save only the reproductive; these develop only when the first host is swallowed by the second or final host, in which case the parasite attaches itself to the wall of the alimentary canal and

A curious feature shared by both larva and adult is the large size of many of the cells, e.g. the nerve cells and the bell.

O. Hamann has divided the group into three families, to which a fourth must be added.

(i.) Fam. Echinorhynchidae.This is by far the largest family and contains the commonest species; the larva of Echinorhynchus proteus lives in Gammarus pulex and in small fish, the adult is common in many fresh-water fish: E. polymorphus, larval host the crayfish, adult host the duck: E. angustotus occurs as a larva in Asellus aquaticus, as an adult in the perch, pike and barbel: E. moniliformis has for its larval host the larvae of the beetle Blaps mucronata, for its final host certain mice, if introduced into man it lives well: E. acus is common in whiting: E. porrigeus in the fin-whale, and E. strumosus in the seal. A species named E. hominis has been described from a boy. (ii.) Fam. Gigantorhynchidae. A small family of large forms with a ringed and flattened body. Gigantorhynchus gigas lives normally in the pig, but is not uncommon in man in South Russia, its larval host is the grub of Melolontha vulgaris, Cetonis auratus, and in America probably of Lachnosterna arcuata: G. echinodiscus lives in the intestine of ant-eaters: G. spira in that of the



Fig. 4. A, The larva of Echinorhynchus proteus from the body cavity of Phoxinus laevis, with the proboscis retracted and the whole still enclosed in a capsule. B, A section through the same; a, the invaginated proboscis; b, proboscis sheath; c, beginning of the neck; d, lemniscus. Highly
magnified (both from Hamann). king vulture, Sarcorhampus papa, and G. taeniodes in Dicholopus cristatus, a cariama.

(iii.) Fam. Neorhynchidae. Sexually mature whilst still in the larval stage. Neorhynchus clavaeceps in Cyprinus carpio has its larval form in the larva of Sialis lularia and in the leech Nephelis octcculii: tact K. agilis is found in Mugil auratus and M. cephalus.

(iv.) Apororhynchidae. With no proboscis. This family contains the single species Apororhynchus hemignathi, found near the anus of Hemignathiis procerus, a Sandwich Island bird.

Fig. 5. — Fully formed larva of Echinorhynchus proteus from the body cavity of Phoxinus laevis (from Hamann). Highly magnified. a, Proboscis; b, bulla; c, neck; d, trunk; e, e, lemnisci.

AUTHORITIES. - O. Hamann, O. Jen. Zeitschr. xxv., 1891, p. 113; Zool. Anz. xv., 1892, 195; J. Kaiser, Bibl. Zool. ii., 1893: A. E. Shipley, Quart. Journ. Micr. Sci. Villot, Zool. Anz. viii., 1885, p. 19. (A. E. S.)

ACANTHUS (the Greek and Latin name for the plant, connected with ake, a sharp point), a genus of plants belonging to the natural order Acanthaceae. The species are natives of the southern parts of Europe and the warmer parts of Asia and Africa. The best-known is Acanthus mollis (brank-ursine, or bears' breech), a common species throughout the Mediterranean region, having large, deeply cut, hairy, shining leaves. Another species, Acanthus spinosus, is so called from its spiny heaves. They are bold, handsome plants, with stately spikes, 2 to 3 ft. high, of flowers with spiny bracts. A. mollis, A. lalifolius and A. longifolius are broad-leaved species; A. spinosus and A. spinosissimus have narrower, spiny toothed leaves. In decoration, the acanthus was first reproduced in metal, and subsequently carved in stone by the Greeks. It was afterwards, with various changes, adopted in all succeeding styles of architecture as a basis of ornamental decoration. There are two types, that found in the Acanthus spinosus, which was followed by the Greeks, and that in the Acanthus mollis, which seems to have been preferred by the Romans.

ACAPULCO, a city and port of the state of Guerrero on the Pacific coast of Mexico, 190 m. S.S.W. of the city of Mexico, Pop. (1900) 4932. It is located on a deep, semicircular bay, almost land-locked, easy of access, and with so secure an anchorage that vessels can safely lie alongside the rocks that fringe the shore. It is the best harbour on the Pacific coast of Mexico, and it is a port of Call for steamship lines running between Panama and San Francisco. The town is built on a narrow strip of low land, scarcely half a mile wide, between the shore line and the lofty mountains that encircle the bay. There is great natural beauty in the surroundings, but the mountains render the town difficult of access from the interior, and give it an exceptionally hot and unhealthy climate. The effort to admit the cooling sea breezes by cutting through the mountains a passage called the Abra de San Nicolas had some beneficial effect. Acapulco was long the most important Mexican port on the Pacific, and the only depot for the Spanish fleets plying between Mexico and Spain's East Indian colonies from 1778 until the independence of Mexico, when this trade was lost. The town has been chosen as the terminus for two railway lines seeking a Pacific port—the Interoceanic and the Mexican Central. The town suffered considerably from earthquakes in July and August 1909. There are exports of hides, cedar and fruit, and the adjacent district of Tabares produces cotton, tobacco, cacao, sugar cane, Indian corn, beans and coffee.

ACARNANIA, a district of ancient Greece, bounded on the W. by the Ionian Sea, on the N. by the Ambracian Gulf, on the E. and S. by Mt. Thyamus and the Acholous. The Echinades islands, off the S.W. coast, are gradually being joined up to the mainland. Its most populous region was the plain of the Acholous, commanded by the principal town Stratus; communication with the coast was impeded by mountain ridges and lagoons. Its people long continued in semi-barbarism, having little intercourse with the rest of Greece. In the 5th century B.C. with the aid of Athens they subdued the Corinthian factories on their coast. In 391 they submitted to the Spartan king Agesilaus; in 371 they passed under Theban control. In the Hellenistic age the Acarnanians were constantly assailed by their Aetolian neighbours. On the advice of Cassander they made effective their ancient cantonal league, apparently after the pattern of Aetolla. In the 3rd century they obtained assistance from the Illyrians, and formed a close alliance with Philip V. of Macedonia, whom they supported in his Roman wars, their new federal capital, Lencas, standing a siege in his interest. For their sympathy with his successor Perseus they were deprived of Lencas and required to send hostages to Rome (167). The country was finally desolated by Augustus, who drafted its inhabitants into Nicopoiis and Patrae. Acarnania took a prominent part in the national uprising of 1821; it is now joined with Aetolia as a nome. The sites of several ancient towns in Acarnania are marked by well preserved walls, especially those of Stratus, Oeniadae and Limnaea.

AUTHORITIES.-Strabo vii. 7, x. 2; Thucydides; Polybius iv. 40; Livy xxxiii. 16-17; Corpus Inscr. Graecarum, no. 1739; E. Oberhummer, Akarnanien im Altertum (Munich, 1887); Heuzey, Mt. Olympe et l'Acarnanie (Paris, 1860). (M. O. B. C.; E. GR.)

ACARUS (from Gr. akari, a mite), a genus of Arachnids, represented by the cheese mite and other forms.

ACASTUS, in Greek legend, the son of Pohas, king of Iolcus in Thessaly (Ovid, Metam. vili. 306; Apollonius Rhodius i. 224; Pindar, Nemea, iv. 54, v. 26). He was a great friend of Jason, and took part in the Calydonian boar-hunt and the Argonautic expedition. After his father's death he instituted splendid funeral games in his honour, which were celebrated by artists and poets, such as Stesichorus. His wife Astydameia (called Hippolyte in Horace, Odes, iii. 7. 17) fell in love with Peleus (q.v.), who had taken refuge at Iolcus, but when her advances were rejected accused him falsely to her husband. Acastus, to avenge his fancied wrongs, left Peleus asleep on Mount Pellon, having first hidden his famous sword. On awaking, Peleus was attacked by the Centaurs, but saved by Cheiron. Having re-covered his sword he returned to Iolcus and slew Acastus and Astydameia. Acastus was represented with his famous horses in the painting of the Argonautic expedition by Micon in the temple of the Dioscuri at Athens.

ACATALEPSY (Gr. a-, privative, and katalambanein, to seize), a term used in Scepticism to denote incomprehensibility.

ACAULESCENT (Lat. acaulescens, becoming stemless, from a, not, and caulis, a stem), a term used of a plant apparently stemless, as dandelion, the stem being almost suppressed.

ACCA LARENTIA (not Laurentia), in Roman legend, the wife of the shepherd Faustulus, who saved the lives of the twins Romulus and Remus after they had been thrown into the Tiber. She had twelve sons, and on the death of one of them Romulus took his place, and with the remaining eleven founded the college of the Arval brothers (Fratres Arvales). The tradition that Romulus and Remus were suckled by a wolf has been explained by the suggestion that Larentia was called lupa ("courtesan'', literally "she-wolf'') on account of her immoral character (Livy i. 4; Ovid, Fasti, iii. 55). According to another account, Larentia was a beautiful girl, whom Hercules won in a game of dice (Macrobius i. 10; Plutarch, Romulus, 4, 5, Quaest. Rom. 35; Aulus Genius vi. 7). The god advised her to marry the first man she met in the street, who proved to be a wealthy Etruscan named Tarutius. She inherited all his property and bequeathed it to the Roman people, who out of gratitude instituted in her honour a yearly festival called Larentalia (Dec. 23). According to some, Acca Larentia was the mother of the Lares, and, like Ceres, Teilus, Flora and others, symbolized the fertility of the earth—in particular the city lands and their crops.

See Mommsen, "Die echte und die falsche Larentia,'' in Romische Forschungen, ii. 1879; E. Pais, Ancient Legends of Roman History (Eng. trans. 1906) whose views on the subject are criticized by W. W. Fowler in W. H. D. Rouse's The Year's Work in Classical Studies (1907); C. Pascal, Studii di alntichita e Mitologia (1896).

ACCELERATION (from Lat. accelerare, to hasten, celer, quick), hastening or quickening; in mechanics, a term employed to denote the rate at which the velocity of a body, whose motion is not uniform, either increases or decreases. (See MECHANICS and HODOGRAPH.)

ACCENT. The word "accent'' has its origin in the Lat. accentus, which in its turn is a literal translation of the Gr. prosodia. The early Greek grammarians used this term for the musical accent which characterized their own language, but later the term became specialized for quantity in metre, whence comes the Eng. prosody. Besides various later developments of usage it is important to observe that "accent'' is used in two different and often contrasted senses in connexion with language. In all languages there are two kinds of accent: (1) musical chromatic or pitch accent; (2) emphatic or stress accent. The former indicates differences in musical pitch between one sound and another in speech, the latter the difference between one syllable and another which is occasioned by emitting the breath in the production of one syllable with greater energy than is employed for the other syllables of the same word. These two senses, it is to be noticed, are different from the common usage of the word in the statement that some one talks with a foreign or with a vulgar accent. In these cases, no doubt, both differences of intonation and differences of stress may be included in the statement, but other elements are frequently no less marked, e.g. the pronunciation of t and d as real dentals, whereas the English sounds so described are really produced not against the teeth but against their sockets, the inability to produce the interdental th whether breathed as in thin or voiced as in this and its representation by d or z, the production of o as a uniform sound instead of one ending as in English in a slight u sound, or such dialect changes as lydy (laidy) for lady, or toime for time (taime).

In different languages the relations between pitch and stress differ very greatly. In some the pitch or musical accent predominates. In such languages if signs are employed to mark the position of the chief accent in the word it will be the pitch and not the stress accent which will be thus indicated. Amongst the languages of ancient times Sanskrit and Greek both indicate by signs the position of the chief pitch accent in the word, and the same method has been employed in modern times for languages in which pitch accent is welf marked, as it is, for example in Lithuanian, the language still spoken by some two millions of people on the frontier between Prussia and Russia in the neighbourhood of Konigsberg and Vilna. Swedish also has a well-marked musical accent. Modern Greek has changed from pitch to stress, the stress being generally laid upon the same syllable in modern as bore the pitch accent in ancient Greek.

In the majority of European languages, however, stress is more conspicuous than pitch, and there is plenty of evidence to show that the original language from which Greek, Latin, Celtic, Teutonic, Slavonic and other languages of Europe are descended, possessed stress accent also in a marked degree. To the existence of this accent must be attributed a large part of the phenomena known as Ablaut or Gradation (see INDO-EUROPEAN LANGUAGES). In modern languages we can see the same principle at work making Acton out of the O. Eng. (Anglo-Saxon) ac-tun (oak-town), and in more recent times producing the contrast between New Town and Newton. In French, stress is less marked than it is in English, but here also there is evidence to show that in the development from Latin to French a very strong stress accent must have existed. The natural result of producing one syllable of a word with greater energy than the others is that the other syllables have a less proportion of breath assigned to them and therefore tend to become indistinct or altogether inaudible. Thus the strong stress accent existing in the transition period between Latin and French led to the curtailing of long Latin words like latrocinium or hospitale into the words which we have borrowed from French into English as larceny and hotel. It will be observed that the first syllable and that which bears the accent are the two which best withstand change, though the strong tendency in English to stress heavily the first syllable bids fair ultimately to oust the e in the pronunciation of larceny. No such changes arise when a strong pitch accent is accompanied by a weaker stress accent, and hence languages like ancient Sanskrit and ancient Greek, where such conditions existed, preserve fuller forms than their sister languages or than even their own descendants, when stress takes the place of pitch as the more important element in accent.

In both pitch and stress accent different gradations may be observed. In pitch, the accent may be uniform, rising or falling. Or there may be combinations of rising and falling or of falling and rising accents upon the same syllable. In ancient Greek, as is well known, three accents are distinguished—(1) the acute ('), a rising accent; (2) the grave ('), apparently merely the indication that in particular positions in the sentence the acute accent is not used where it would occur in the isolated word; and (3) the circumflex, which, as its form (^) shows, and as the ancient grammarians inform us, is a combination of the rising and the falling accent upon the same syllable, this syllable being always long. Different Greek dialects, however, varied the syllables of the word on which the accent occurred, Aeolic Greek, for example, never putting the acute on the last syllable of a word, while Attic Greek had many words so accented.

The pitch accent of the Indo-European languages was originally free, i.e. might occur on any syllable of a word, and this condition of things is still found in the earliest Sanskrit literature. But in Greek before historical times the accent had become limited to the last three syllables of a word, so that a long word like the Homeric genitive feromenoio could in no circumstances be accented on either of its first two syllables, while if the final syllable was long, as in the accusative plural feromenous, the accent could go back only to the second syllable from the end. As every vowel has its own natural pitch, and a frequent interchange between e ( a high vowel) and o (a low vowel) occurs in the Indo-European languages, it has been suggested that e originally went with the highest pitch accent, while o appeared in syllables of a lower pitch. But if there is any foundation for the theory, which is by no means certain, its effects have been distorted and modified by all manner of analogical processes. Thus poimen with acute accent and daimon with the acute accent on the preceding syllable would correspond to the rule, so would aletes and epos, but there are many exceptions like odos where the acute accent accompanies an o vowel. Somewhat similar distinctions characterize syllables which are stressed. The strength of the expiration may be greatest either at the beginning, the end or the middle of the syllable, and, according as it is so, the accent is a failing, a rising, or a rising and falling one. Syllables in which the stress is produced continuously whether increasing or decreasing are called single-pointed syllables, those in which a variation in the stress occurs without being strong enough to break the syllable into two are called double-pointed syllables. These last occur in some English dialects, but are commonest in languages like Swedish and Lithuanian, which have a "sing-song'' pronunciation. It is often not easy to decide whether a syllable is double-pointed or whether what we hear is really two-single-pointed syllables. There is no separate notation for stress accent, but the acute (') is used for the increasing, the grave (') for the decreasing stress, and the circumflex (^) for the rising and falling (increasing and decreasing) and (@) for the opposite. A separate notation is much to be desired, as the nature of the two accents is so different, and could easily be devised by using (@) for the falling, (') for the rising stress, and (@) for the combination of the two in one syllable. This would be clearer than the upright stroke ( ) preceding the stressed syllable, which is used in some phonetic works.

The relation between the two accents in the same language at the same time is a subject which requires further investigation. It is generally assumed that the chief stress and the chief pitch in a word coincide, but this is by no means certain for all cases, though the incidence of the chief stress accent in modern Greek upon the same syllable as had the chief pitch accent in ancient times suggests that the two did frequently fall upon the same syllable. On the other hand, in words like the Sanskrit sapta, the Gr. epta, the pitch accent which those languages indicate is upon a syllable which certainly, in the earliest times at least, did not possess the principal stress. For forms in other languages, like the Lat. septem or the Gothic sibun, show that the a of the final syllables in Sanskrit and Greek is the representative of a reduced syllable in which, even in the earliest times, the nasal alone existed (see under N for the history of these so-called sonant nasals). It is possible that sporadic changes of accent, as in the Gr. meter compared with the Sanskrit mata, is owing to the shifting of the pitch accent to the same syllable as the stress occupied.

There is no lack of evidence to show that the stress accent also may shift its position in the history of a language from one syllable to another. In prehistoric times the stress in Latin must have rested upon the first syllable in all cases. Only on this hypothesis can be explained forms like peperci (perfect of parco) and collido (a compound of laedo). In historical times, when the stress in Latin was on the second syllable from the end of the word if that syllable was long, or on the third syllable from the end if the second from the end was short, we should have expected to find *peparci and *collaedo, for throughout the historical period the stress rested in these words upon the second syllable from the end. The causes for the change of position are not always easy to ascertain. In words of four syllables with a long penult and words of five syllables with a short penult there probably developed a secondary accent which in course of time replaced the earlier accent upon the first syllable. But the number of such long words in Latin is comparatively small. It is no less possible that relations between the stress and pitch accents were concerned. For unless we are to regard the testimony of the ancient Latin grammarians as altogether untrustworthy there was at least in classical Latin a well-marked pitch as well as a stress accent. This question, which had long slumbered, has been revived by Dr J. Vendryes in his treatise entitled Recherches sur l'histoire et les effets de l'intensite initiale en latin (Paris, 1902).

In English there is a tendency to throw the stress on to the first syllable, which leads in time to the modification of borrowed words. Thus throughout the 18th century there was a struggle going on over the word balcony, which earlier was pronounced balcony. Swift is the first author quoted for the pronunciation balcony. and Cowper's balcony in "John Gilpin'' is among the latest instances of the old pronunciation. Disregarding the Latin quantity of orator and senator, English by throwing the stress on the first syllable has converted them into orator and senator, while Scots lawyers speak also of a curator. How far French influence plays a part here is not easy to say.

Besides the accent of the syllable and of the word, which have been already discussed, there remains the accent of the sentence. Here the problem is much more complicated. The accent of a word, whether pitch or stress, may be considerably modified in the sentence. From earliest times some words have become parasitic or enclitic upon other words. Pronouns more than most words are modified from this cause, but conjunctions like the Gr. te ("and''), the Lat. qiie, have throughout their whole history been enclitic upon the preceding word. A very important word may be enclitic, as in English don't, shan't. It is to be remembered that the unit of language is rather the sentence than the word, and that the form which is given to the word in the dictionary is very often not the form which it takes in actual speech. The divisions of words in speech are quite different from the divisions on the printed page. Sanskrit alone amongst languages has consistently recognized this, and preserves in writing the exact combinations that are spoken.

Accent, whether pitch or stress, can be utilized in the sentence to express a great variety of meanings. Thus in English a sentence like You rode to Newmarket yesterday, which contains five words, may be made to express five different statements by putting the stress upon each of the words in turn. By putting the stress on you the person addressed is marked out as distinct from certain others, by putting it upon rode other means of locomotion to Newmarket are excluded, and so on. With the same order of words five interrogative sentences may also be expressed, and a third series of exclamatory sentences expressing anger, incredulity, &c., may be obtained from the same words. It is to be noticed that for these two series a different intonation, a different musical (pitch) accent appears from that which is found in the same words when employed to make a matter-of-fact statement.

In languages like Chinese, which have neither compound words nor inflection, accent plays a very important part. As the words are all monosyllabic, stress could obviously not be so important as pitch as a help to distinguish different senses attached to the same syllable, and in no other language is variety of pitch so well developed as in Chinese. In languages which, like English, show comparatively little pitch accent it is to be noticed that the sentence tends to develop a more musical character under the influence of emotion. The voice is raised and at the same time greater stress is generally employed when the speaker is carried away by emotion, though the connexion is not essential and strong emotion may be expressed by a lowering as well as by a raising of the voice. In either case, however, the stress will be greater than the normal.

BIBLIOGRAPHY.—H. Sweet, Primer of Phonetics (1890, now in 3rd edition), sec. 96 ff., History of English Sounds (1888), sec. 110 ff., and other works; E. Sievers, Grundzuge der Phonetik (1893), sec. 532 ff.; O. Jespersen, Lehrbuch der Phonetik (1904), an abbreviated German translation of the author's larger work in Danish, sec. 216 ff. The books of Sievers and Jespersen give (especially Sievers) full references to the literature of the subject. For the accent system of the Indo-European languages see "Betonung'' in Brugmann's Grundriss der vergleichenden Grammatik der indogermanischen Sprachen, vol. i. (1897), or, with considerable modifications, his Kurze vergleichende Grammatik der idg. Sprachen (1902), sec. sec. 32-65 and 343-350. (P. Gi.)

ACCEPTANCE (Lat. acceptare, frequentative form of accipere, to receive), generally, a receiving or acknowledgment of receipt; in law, the act by which a person binds himself to comply with the request contained in a bill of exchange (q.v.), addressed to him by the drawer. In all cases it is understood to be a promise to pay the bill in money, the law not recognizing an acceptance in which the promise is to pay in some other way, e.g. partly in money and partly by another bill. Acceptance may be either general or qualified. A general acceptance is an engagement to pay the bill strictly according to its tenor, and is made by the drawee subscribing his name, with or without the word "accepted,'' at the bottom of the bill, or across the face of it. Qualified acceptance may be a promise to pay on a contingency occurring, e.g. on the sale of certain goods consigned by the drawer to the acceptor. No contingency is allowed to be mentioned in the body of the bill, but a qualified acceptance is quite legal, and equally binding with a general acceptance upon the acceptor when the contingency bas occurred. It is also qualified acceptance where the promise is to pay only part of the sum mentioned in the bill, or to pay at a different time or place from those specified. As a qualified acceptance is so far a disregard of the drawer's order, the holder is not obliged to take it; and if he chooses to take it he must give notice to antecedent parties, acting at his own risk if they dissent. In all cases acceptance involves the signature of the acceptor either by himself or by some person duly authorized on his behalf. A bill can be accepted in the first instance only by the person or persons to whom it is addressed; but if he or they fail to do so, it may, after being protested for non-acceptance, be accepted by some one else "supra protest,'' for the sake of the honour of one or more of the parties concerned in it, and he thereupon acquires a claim against the drawer and all those to whom he could have resorted.

ACCEPTILATION (from Lat. acceptilatio), in Roman and Scots law, a verbal release of a verbal obligation. This formal mode of extinguishing an obligation contracted verbally received its name from the book-keeping term acceptilatio, entering a receipt, i.e. carrying it to credit. The words conveying the release had to correspond to, or strictly cover, the expressed obligation. Figuratively, in theology, the word acceptilation means free remission or forgiveness of sins.

ACCESS (Lat. accessus), approach, or the means of approaching. In law, the word is used in various connexions. The presumption of a child's legitimacy is negatived if it be proved that a husband has not had access to his wife within such a period of time as would admit of his being the father. (See LEGITIMACY.) In the law of easements, every person who has land adjoining a public road or a public navigable river has a right of access to it from his land. So, also, every person has a right of access to air and light from an ancient window. For the right of access of parents to children under the guardianship of the court, see INFANT.

ACCESSION (from Lat. accedere, to go to, to approach), in law, a method of acquiring property adopted from Roman law, by which, in things that have a close connexion with or dependence on one another, the property of the principal draws after it the property of the accessory, according to the principle, accessio cedet principali. Accession may take place either in a natural way, such as the growth of fruit or the pregnancy of animals, or in an artificial way. The various methods may be classified as (1) land to land by accretion or alluvion; (2) moveables to land (see FIXTURES); (3) moveables to moveables; (4) moveables added to by the art or industry of man; this may be by specification, as when wine is made out of grapes, or by confusion, or commixture, which is the mixing together of liquids or solids, respectively. In the case of industrial accession ownership is determined according as the natural or manufactured substance is of the more importance, and, in general, compensation is payable to the person who has been dispossessed of his property.

In a historical or constitutional sense, the term "accession'' is applied to the coming to the throne of a dynasty or line of sovereigns or of a single sovereign.

"Accession'' sometimes likewise signifies consent or acquiescence. Thus, in the bankruptcy law of Scotland, where there is a settlement by a trust-deed, it is accepted on the part of each creditor by a "deed of accession.''

ACCESSORY, a person guilty of a felonious offence, not as principal, but by participation; as by advice, command, aid or concealment. In certain crimes, there can be no accessories; all concerned being principals, whether present or absent at the time of their commission. These are treason, and all offences below the degree of felony, as specified in the Offences against the Person Act 1861.

There are two kinds of accessories — before the fact, and after it. The first is he who commands or procures another to commit felony, and is not present himself; for if he be present, he is a principal. The second is he who receives, harbours, assists, or comforts any man that has done murder or felony, whereof he has knowledge. An accessory before the fact is liable to the same punishment as the principal; and there is now indeed no practical difference between such an accessory and a principal in regard either to indictment, trial or punishment. Accessories after the fact are in general punishable with imprisonment (with or without hard labour) for a period not exceeding two years, but in the case of murder punishable by penal servitude for life, or not less than three years, or by imprisonment (with or without hard labour) to the extent of two years. The law of Scotland makes no distinction between the accessory to any crime and the principal (see ART AND PART). Except in the case of treason, accession after the fact is not noticed by the law of Scotland unless as an element of evidence to prove previous accession.

ACCIAJUOLI, DONATO (1428-1478), Italian scholar, was born at Florence in 1428. He was famous for his learning, especially in Greek and mathematics, and for his services to his native state. Having previously been entrusted with several important embassies, he became Gonfalonier of Florence in 1473. He died at Milan in 1478, when on his way to Paris to ask the aid of Louis XI. on behalf of the Florentines against Pope Sixtus IV. His body was taken back to Florence, and buried in the church of the Carthusians at the public expense, and his daughters were portioned by his fellow-citizens, the fortune he left being, owing to his probity and disinterestedness, very small. He wrote a Latin translation of some of Plutarch's Lives (Florence, 1478); Commentaries on Aristotle's Ethics and Politics; and the lives of Hannibal, Scipio and Charlemagne. In the work on Aristotle he had the co-operation of his master Argyropulus.

ACCIDENCE (a mis-spelling of "accidents,'' from the Latin neuter plural accidentia, casual events), the term for the grammatical changes to which words are subject in their inflections as to gender, number, tense and case. It is also used to denote a book containing the first principles of grammar, and so of the rudiments of any subject or art.

ACCIDENT (from Lat. accidere, to happen), a word of widely variant meanings, usually something fortuitous and unexpected; a happening out of the ordinary course of things. In the law of tort, it is defined as "an occurrence which is due neither to design nor to negligence''; in equity, as "such an unforeseen event, misfortune, loss, act or omission, as is not the result of any negligence or misconduct.'' So, in criminal law, "an effect is said to be accidental when the act by which it is caused is not done with the intention of causing it, and when its occurrence as a conseiguence of such act is not so probable that a person of ordinary prudence ought, under the circumstances, to take reasonable precaution against it'' (Stephen, Digest of Criminal Law, art. 210).The word may also have in law the more extended meaning of an unexpected occurrence, whether caused by any one's negligence or not, as in the Fatal Accidents Act 1846, Notice of Accidents Act 1894. See also CONTRACT, CRIMINAL LAW, EMPLOYERS' LIABILITY, INSURANCE, TORT, &c.

In logic an "accident'' is a quality which belongs to a subject but not as part of its essence (in Aristotelian language kata sumbebekos, the scholastic per accidens). Essential attributes are necessarily, or causally, connected with the subject, e.g. the sum of the angles of a triangle; accidents are not deducible from the nature, or are not part of the necessary connotation, of the subject, e.g. the area of a triangle. It follows that increased knowledge, e.g. in chemistry, may show that what was thought to be an accident is really an essential attribute, or vice versa. It is very generally held that, in reality, there is no such thing as an accident, inasmuch as complete knowledge would establish a causal connexion for all attributes. An accident is thus merely an unexplained attribute. Accidents have been classed as (1) "inseparable,'' i.e. universally present, though no causal connexion is established, and (2) "separable,'' where the connexion is neither causally explained nor universal. Propositions expressing a relation between a subject and an accident are classed as "accidental,'' "real'' or "ampliative,'' as opposed to "verbal'' or "analytical,'' which merely express a known connexion, e.g. between a subject and its connotation (q.v.).

ACCIDENTALISM, a term used (1) in philosophy for any system of thought which denies the causal nexus and maintains that events succeed one another haphazard or by chance (not in the mathematical but in the popular sense). In metaphysics, accidentalism denies the doctrine that everything occurs or results from a definite cause. In this connexion it is synonymous with Tychism (tuchu, chance), a term used by C. S. Peirce for the theories which make chance an objective factor in the process of the Universe. Opponents of this accidentalism maintain that what seems to be the result of chance is in reality due to a cause or causes which, owing to the lack of imagination, knowledge or scientific instruments, we are unable to detect. In ethics the term is used, like indeterminism, to denote the theory that mental change cannot always be ascribed to previously ascertained psychological states, and that volition is not causally related to the motives involved. An example of this theory is the doctrine of the liberum arbitrium indifferentiae ("liberty of indifference''), according to which the choice of two or more alternative possibilities is affected neither by contemporaneous data of an ethical or prudential kind nor by crystallized habit (character). (2) In painting, the term is used for the effect produced by accidental lights (Ruskin, Modern Painters, I. II. 4, iii. sec. 4, 287). (3) In medicine, it stands for the hypothesis that disease is only an accidental modification of the healthy condition, and can, therefore, be avoided by modifying external conditions.

ACCIUS, a Latin poet of the 16th century, to whom is attributed a paraphrase of Aesop's Fables, of which Julius Scaliger speaks with great praise.

ACCIUS, LUCIUS, Roman tragic poet, the son of a freedman, was born at Pisaurum in Umbria, in 170 B.C. The year of his death is unknown, but he must have lived to a great age, since Cicero (Brutus, 28) speaks of having conversed with him on literary matters. He was a prolific writer and enjoyed a very high reputation (Horace, Epistles, ii. 1, 56; Cicero, Pro Plancio, 24). The titles and considerable fragments (about 700 lines) of some fifty plays have been preserved. Most of these were free translations from the Greek, his favourite subjects being the legends of the Trojan war and the house of Pelops. The national history, however, furnished the theme of the Brutus and Decius, —-the expulsion of the Tarquins and the self-sacrifice of Publius Decius Mus the younger. The fragments are written in vigorous language and show a lively power of description.

Accius wrote other works of a literary character: Didascalicon and Pragmaticon libri, treatises in verse on the history of Greek and Roman poetry, and dramatic art in particular; Parerga and Praxidica (perhaps identical) on agriculture; and an Annales. He also introduced innovations in orthography and grammar.

See Boissier, Le Poete Accius, 1856; L. Muller, De Accii fabulis Disputatio (1890); Ribbeck, Geschichte der romischen Dichtung (1892); editions of the tragic fragments by Ribbeck (1897), of the others by Bahrens (1886); Plessis, Poesue Latine (1909).

ACCLAMATION (Lat. acclamatio, a shouting at), in deliberative or electoral assemblies, a spontaneous shout of approval or praise. Acclamation is thus the adoption of a resolution or the passing of a vote of confidence or choice unanimously, in direct distinction from a formal ballot or division. In the Roman senate opinions were expressed and votes passed by acclamation in such forms as Omnes, omnes, Aequum est, Justum est, &c.; and the praises of the emperor were celebrated in certain pre-arranged sentences, which seem to have been chanted by the whole body of senators. In ecclesiastical councils vote by acclamation is very common, the question being usually put in the form, placet or non placet. The Sacred College has sometimes elected popes by acclamation, when the cardinals simultaneously and without any previous consultation "acclaimed'' one of their number as pontiff. A further ecclesiastical use of the word is in its application to set forms of praise or thanksgiving in church services, the stereotyped responses of the congregation. In modern parliamentary usage a motion is carried by acclamation when, no amendment being proposed, approval is expressed by shouting such words as Aye or Agreed.

ACCLIMATIZATION, the process of adaptation by which animals and plants are gradually rendered capable of surviving and flourishing in countries remote from their original habitats, or under meteorological conditions different from those which they have usually to endure, and at first injurious to them.

The subject of acclimatization is very little understood, and some writers have even denied that it can ever take place. It is often confounded with domestication or with naturalization; but these are both very different phenomena. A domesticated animal or a cultivated plant need not necessarily be acclimatized; that is, it need not be capable of enduring the severity of the seasons without protection. The canary bird is domesticated but not acclimatized, and many of our most extensively cultivated plants are in the same category. A naturalized animal or plant, on the other hand, must be able to withstand all the vicissitudes of the seasons in its new home, and it may therefore be thought that if must have become acclimatized. But in many, perhaps most cases of naturalization (see Appendix below) there is no evidence of a gradual adaptation to new conditions which were at first injurious, and this is essential to the idea of acclimatization. On the contrary, many species, in a new country and under somewhat different climatic conditions, seem to find a more congenial abode than in their native land, and at once flourish and increase in it to such an extent as often to exterminate the indigenous inhabitants. Thus L. Agassiz (in his work on Lake Superior) tells us that the roadside weeds of the north-eastern United States, to the number of 130 species, are all European, the native weeds having disappeared westwards; while in New Zealand there are, according to T. Kirk (Transactions of the New Zealand Institute, vol. ii. p. 131), no less than 250 species of naturalized plants, more than 100 of which spread widely over the country and often displace the native vegetation. Among animals, the European rat, goat and pig are naturalized in New Zealand, where they multiply to such an extent as to injure and probably exterminate many native productions. In none of these cases is there any indication that acclimatization was necessary or ever took place.

On the other hand, the fact that an animal or plant cannot be naturalized is no proof that it is not acclimatized. It has been shown by C. Darwin that, in the case of most animals and plants in a state of nature, the competition of other organisms is a far more efficient agency in limiting their distribution than the mere influence of climate. We have a proof of this in the fact that so few, comparatively, of our perfectly hardy garden plants ever run wild; and even the most persevering attempts to naturalize them usually fail. Alphonse de Candolle (Geographic botanique, p. 798) informs us that several botanists of Patis, Geneva, and especially of Montpellier, have sown the seeds of many hundreds of species of exotic hardy plants, in what appeared to be the most favourable situations, but that in hardly a single case has any one of them become naturalized. Attempts have also been made to naturalize continental insects in Britain, in places where the proper food-plants abound and the conditions seem generally favourable, but in no case do they seem to have succeeded. Even a plant like the potato, so largely cultivated and so perfectly hardy, has not established itself in a wild state in any part of Europe.

Different Degrees of Climatal Adaptation in Animals and Plants.—-Plants differ greatly from animals in the closeness of their adaptation to meteorological conditions. Not only will most tropical plants refuse to live in a temperate climate, but many species are seriously injured by removal a few degrees of latitude beyond their natural limits. This is probably due to the fact, established by the experiments of A. C. Becquerel, that plants possess no proper temperature, but are wholly dependent on that of the surrounding medium.

Animals, especially the higher forms, are much less sensitive to change of temperature, as shown by the extensive range from north to south of many species. Thus, the tiger ranges from the equator to northern Asia as far as the river Amur, and to the isothermal of 32 deg. Fahr. The mountain sparrow (Fasser montana) is abundant in Java and Singapore in a uniform equatorial climate, and also inhabits Britain and a considerable portion of northern Europe. It is true that most terrestrial animals are restricted to countries not possessing a great range of temperature or very diversified climates, but there is reason to believe that this is due to quite a different set of causes, such as the presence of enemies or deficiency of appropriate food. When suppllad with food and partially protected from enemies, they often show a wonderful capacity of enduring climates very different from that in which they originally flourished. Thus, the horse and the domestic fowl, both natives of very warm countries, flourish without special protection in almost every inhabited portion of the globe. The parrot tribe form one of the most pre-eminently tropical groups of birds, only a few species extending into the warmer temperate regions; yet even the most exclusively tropical genera are by no means delicate birds as regards climate. In the Annals and Magazine of Natural History for 1868 (p. 381) is a most interesting account, by Charles Buxton, of the naturalization of parrots at Northrops Hall, Norfolk. A considerable number of African and Amazonian parrots, Bengal parroquets, four species of white and rose crested cockatoos, and two species of crimson lories, remained at large for many years. Several of these birds bred, and they almost all lived in the woods the whole year through, refusing to take shelter in a house constructed for their use. Even when the thermometer fell 6 deg. below zero, all appeared in good spirits and vigorous health. Some of these birds have lived thus exposed for many years, enduring the English cold easterly winds, rain, hail and snow, all through the winter—a marvellous contrast to the equable equatorial temperature (hardly ever less than 70 deg. ) to which many of them had been accustomed for the first year or years of their existence. Similarly the recent experience of zoological gardens, particularly in the case of parrots and monkeys, shows that, excluding draughts, exposure to changes of temperature without artificial heat is markedly beneficial as compared with the older method of strict protection from cold.

Hardly any group of Mammalia is more exclusively tropical than the Quadrumana, yet, if other conditions are favourable, some of them can withstand a considerable degree of cold. Semnopithecus schistaceus was found by Captain Hutton at an elevation of 11,000 feet in the Himalayas, leaping actively among fir-trees whose branches were laden with snow-wreaths. In Abyssinia a troop of dog-faced baboons was observed by W. T. Blanford at 9000 feet above the sea. We may therefore conclude that the restriction of the monkey tribe to warm latitudes is probably determined by other causes than temperature alone.

Similar indications are given by the fact of closely allied species inhabiting very extreme climates. The recently extinct Siberian mammoth and woolly rhinoceros were closely allied to species now inhabiting tropical regions exclusively. Wolves and foxes are found alike in the coldest and hottest parts of the earth, as are closely allied species of falcons, owls, sparrows and numerous genera of waders and aquatic birds.

A consideration of these and many analogous facts might induce us to suppose that, among the higher animals at least, there is little constitutional adaptation to climate, and that in their case acclimatization is not required. But there are numerous examples of domestic animals which show that such adaptation does exist in other cases. The yak of Thibet cannot long survive in the plains of India, or even on the hills below a certain altitude; and that this is due to climate, and not to the increased density of the atmosphere, is shown by the fact that the same animal appears to thrive well in Europe, and even breeds there readily. The Newfoundland dog will not live in India, and the Spanish breed of fowls in this country suffer more from frost than most others. When we get lower in the scale the adaptation is often more marked. Snakes, which are so abundant in warm countries, diminish rapidly as we go north, and wholly cease at lat. 62 deg. . Most insects are also very susceptible to cold, and seem to be adapted to very narrow limits of temperature.

From the foregoing facts and observations we may conclude, firstly, that some plants and many animals are not constitutionally adapted to the climate of their native country only, but are capable of enduring and flourishing under a more or less extensive range of temperature and other climatic conditions; and, secondly, that most plants and some animals are, more or less closely, adapted to climates similar to those of their native habitats. In order to domesticate or naturalize the former class in countries not extremely differing from that from which the species was brought, it will not be necessary to acclimatize, in the strict sense of the word. In the case of the latter class, however, acclimatization is a necessary preliminary to naturalization, and in many cases to useful domestication, and we have therefore to inquire whether it is possible.

Acclimatization by Individual Adaptation.—-It is evident that acclimatization may occur (if it occurs at all) in two ways, either by modifying the constitution of the individual submitted to the new conditions, or by the production of offspring which may be better adapted to those conditions than their parents. The alteration of the constitution of individuals in this direction is not easy to detect, and its possibility has been denied by many writers. C. Darwin believed, however, that there were indications that it occasionally occurred in plants, where it can be best observed, owing to the circumstance that so many plants are propagated by cuttings or buds, which really continue the existence of the same individual almost indefinitely. He adduced the example of vines taken to the West Indies from Madeira, which have been found to succeed better than those taken directly from France. But in most cases habit, however prolonged, appears to have little effect on the constitution of the individual, and the fact has no doubt led to the opinion that acclimatization is impossible. There is indeed little or no evidence to show that any animal to which a new climate is at first prejudicial can be so acclimatized by habit that, after subjection to it for a few or many seasons, it may live as healthily and with as little care as in its native country; yet we may, on general principles, believe that under proper conditions such an acclimatization would take place.

Acclimatization by Variation.—-A mass of evidence exists showing that variations of every conceivable kind occur among the offspring of all plants and animals, and that, in particular, constitutional variations are by no means uncommon. Among cultivated plants, for example, hardier and more tender varieties often arise. The following cases are given by C. Darwin:-Among the numerous fruit-trees raised in North America some are well adapted to the climate of the northern States and Canada, while others only succeed well in the southern States. Adaptation of this kind is sometimes very close, so that, for example, few English varieties of wheat will thrive in Scotland. Seed-wheat from India produced a miserable crop when planted by the Rev. M. J. Berkeley on land which would have produced a good crop of English wheat. Conversely, French wheat taken to the West Indies produced only barren spikes, while native wheat by its side yielded an enormous harvest. Tobacco in Sweden, raised from home-grown seed, ripens its seeds a month earlier than plants grown from foreign seed. In Italy, as long as orange trees were propagated by grafts, they were tender; but after many of the trees were destroyed by the severe frosts of 1709 and 1763, plants were raised from seed, and these were found to be hardier and more productive than the former kinds. Where plants are raised from seed in large quantities, varieties always occur differing in constitution, as well as others differing in form or colour; but the former cannot be perceived by us unless marked out by their behaviour under exceptional conditions, as in the following cases. After the severe winter of 1860-1861 if was observed that in a large bed of araucarias some plants stood quite unhurt among numbers killed around them. In C. Darwin's garden two rows of scarlet runners were entirely killed by frost, except three plants, which had not even the tips of their leaves browned. A very excellent example is to be found in Chinese history, according to E. R. Huc, who, in his L' Empire chinois (tom. ii. p. 359), gives the following extract from the Memoirs of the Emperor Khang:—-"On the 1st day of the 6th moon I was walking in some fields where rice had been sown to be ready for the harvest in the 9th moon. I observed by chance a stalk of rice which was already in ear. It was higher than all the rest, and was ripe enough to be gathered. I ordered it to be brought to me. The grain was very fine and well grown, which gave me the idea to keep it for a trial, and see if the following year it would preserve its precocity. It did so. All the stalks which came from it showed ear before the usual time, and were ripe in the 6th moon. Each year has multiplied the produce of the preceding, and for thirty years it is this rice which has been served at my table. The grain is elongate and of a reddish colour, but it has a sweet smell and very pleasant taste. It is called Vu-mi, Imperial rice, because it was first cultivated in my gardens. It is the only sort which can ripen north of the great wall, where the winter ends late and begins very early; but in the southern provinces, where the climate is milder and the land more fertile, two harvests a year may be easily obtained, and it is for me a sweet reflection to have procured this advantage for my people.'' Huc adds his testimony that this kind of rice flourishes in Manchuria, where no other will grow. We have here, therefore, a perfect example of acclimatization by means of a spontaneous constitutional variation.

That this kind of adaptation may be carried on step by step to more and more extreme climates is illustrated by the following examples. Sweet-peas raised in Calcutta from seed imported from England rarely blossom, and never yield seed; plants from French seed flower better, but are still sterile; but those raised from Darjeeling seed (originally imported from England) both flower and seed profusely. The peach is believed to have been tender, and to have ripened its fruit with difficulty, when first introduced into Greece; so that (as Darwin observes) in travelling northward during two thousand years it must have become much hardier. Sir J. Hooker ascertained the average vertical range of flowering plants in the Himalayas to be 4000 ft., while in some cases if extended to 8000 ft. The same species can thus endure a great difference of temperature; but the important fact is, that the individuals have become acclimatized to the altitude at which they grow, so that seeds gathered near the upper limit of the range of a species will be more hardy than those gathered near the lower limit. This was proved by Hooker to be the case with Himalayan conifers and rhododendrons, raised in Britain from seed gathered at different altitudes.

Among animals exactly analogous facts occur. When geese were first introduced into Bogota they laid few eggs at long intervals, and few of the young survived. By degrees the fecundity improved, and in about twenty years became equal to what it is in Europe. The same author tells us that, according to Garcilaso, when fowls were first introduced into Peru they were not fertile, whereas now they are as much so as in Europe. C. Darwin adduced the following examples. Merino sheep bred at the Cape of Good Hope have been found far better adapted for India than those imported from England; and while the Chinese variety of the Ailanthus silk-moth is quite hardy, the variety found in Bengal will only flourish in warm latitudes. C. Darwin also called attention to the circumstance that writers of agricultural works generally recommend that animals should be removed from one district to another as little as possible. This advice occurs even in classical and Chinese agricultural books as well as in those of our own day, and proves that the close adaptation of each variety or breed to the country in which if originated has always been recognized.

Constitutional Adaptation often accompanied by External Modification.—Although in some cases no perceptible alteration of form or structure occurs when constitutional adaptation to Climate has taken place, in others it is very marked. C. Darwin collected a large number of cases in his Animals and Plants under Domestication.

In his Contributions to the Theory of Natural Selection (p. 167), A. R. Wallace has recorded cases of simultaneous variation among insects, apparently due to climate or other strictly local causes. He found that the butterflies of the family Papilionidae, and some others, became similarly modified in different islands and groups of islands. Thus, the species inhabiting Sumatra, Java and Borneo are almost always much smaller than the closely allied species of Celebes and the Moluccas; the species or varieties of the small island of Amboyna are larger than the same species or closely allied forms inhabiting the surrounding islands; the species found in Celebes possess a peculiar form of wing, quite distinct from that of the same or closely allied species of adjacent islands; and, lastly, numerous species which have tailed wings in India and the western islands of the Archipelago, gradually lose the tail as we proceed eastward to New Guinea and the Pacific.

Many of these curious modifications may, it is true, be due to other causes than climate only, but they serve to show how powerfully and mysteriously local conditions affect the form and structure of both plants and animals; and they render it probable that changes of constitution are also continually produced, although we have, in the majority of cases, no means of detecting them. It is also impossible to determine how far the effects described are produced by spontaneous favourable variations or by the direct action of local conditions; but it is probable that in every case both causes are concerned, although in constantly varying proportions.

Selection and Survival of the Fittest as Agents in Naturalization. —-We may now take it as an established fact that varieties of animals and plants occur, both in domesticity and in a state of nature, which are better or worse adapted to special climates. There is no positive evidence that the influence of new climatal conditions on the parents has any tendency to produce variations in the offspring better adapted to such conditions. Neither does it appear that this class of variations are very frequent. It is, however, certain that whenever any animal or plant is largely propagated constitutional variations will arise, and some of these will be better adapted than others to the climatal and other conditions of the locality. In a state of nature, every recurring severe winter or otherwise unfavourable season weeds out those individuals of tender constitution or imperfect structure which may have got on very well during favourable years, and it is thus that the adaptation of the species to the climate in which it has to exist is kept up. Under domestication the same thing occurs by what C. Darwin has termed "unconscious selection.'' Each cultivator seeks out the kinds of plants best suited to his soil and climate and rejects those which are tender or otherwise unsuitable. The farmer breeds from such of his stock as he finds to thrive best with him, and gets rid of those which suffer from cold, damp or disease. A more or less close adaptation to local conditions is thus brought about, and breeds or races are produced which are sometimes liable to deterioration on removal even to a short distance in the same country, as in numerous cases quoted by C. Darwin (Animals and Plants under Domestication).

The Method of Acclimatization.—Taking into consideration the foregoing facts and illustrations, it may be considered as proved—-1st, That habit has little (though it appears to have some) definite effect in adapting the constitution of animals to a new climate; but that it has a decided, though still slight, influence in plants when, by the process of propagation by buds, shoots or grafts, the individual can be kept under its influence for long periods; 2nd, That great and sudden changes of climate often check reproduction even when the health of the individuals does not appear to suffer. In order, therefore, to have the best chance of acclimatizing any animal or plant in a climate very dissimilar from that of its native country, and in which it has been proved that the species in question cannot live and maintain itself without acclimatization, we must adopt some such plan as the following:—

1. We must transport as large a number as possible of adult healthy individuals to some intermediate station, and increase them as much as possible for some years. Favourable variations of constitution will soon show themselves, and these should be carefully selected to breed from, the tender and unhealthy individuals being rigidly eliminated.

2. As soon as the stock has been kept a sufficient time to pass through all the ordinary extremes of climate, a number of the hardiest may be removed to the more remote station, and the same process gone through, giving protection if necessary while the stock is being increased, but as soon as a large number of healthy individuals are produced, subjecting them to ail the vicissitudes of the Climate. It can hardly be doubted that in most cases this plan would succeed. It has been recommended by C. Darwin, and at one of the early meetings of the Societe Zoologique d' Acclimatation, at Paris, Isodore Geoffroy St Hillaire insisted that it was the only method by which acclimatization was possible. But in looking through the long series of volumes of Reports published by this society, there is no sign that any systematic attempt at acclimatization has even once been made. A number of foreign animals have been introduced, and more or less domesticated, and some useful exotics have been cultivated for the purpose of testing their applicability to French agriculture or horticulture; but neither in the case of animals nor of plants has there been any systematic effort to modify the constitution of the species, by breeding largely and selecting the favourable variations that appeared.

Take the case of the Eucalyptus globulus as an example. This is a Tasmanian gum-tree of very rapid growth and great beauty, which will thrive in the extreme south of France. In the Bulletin of the society a large number of attempts to introduce this tree into general cultivation in other parts of France are recorded in detail, with the failure of almost all of them. But no precautions such as those above indicated appear to have been taken in any of these experiments; and we have no intimation that either the society or any of its members are making systematic efforts to acclimatize the tree. The first step would be, to obtain seed from healthy trees growing in the coldest climate and at the greatest altitude in its native country, sowing these very largely, and in a variety of soils and situations, in a part of France where the climate is somewhat but not much more extreme. It is almost a certainty that a number of trees would be found to be quite hardy. As soon as these produced seed, it should be sown in the same district and farther north in a climate a little more severe. After an exceptionally cold season, seed should be collected from the trees that suffered least, and should be sown in various districts all over France. By such a process there can be hardly any doubt that the tree would be thoroughly acclimatized in any part of France, and in many other countries of central Europe; and more good would be effected by one well-directed effort of this kind than by hundreds of experiments with individual animals and plants, which only serve to show us which are the species that do not require to be acclimatized.

Acclimatization of Man.—-On this subject we have, unfortunately, very little direct or accurate information. The general laws of heredity and variation have been proved to apply to man as well as to animals and plants; and numerous facts in the distribution of races show that man must, in remote ages at least, have been capable of constitutional adaptation to climate. If the human race constitutes a single species, then the mere fact that man now inhabits every region, and is in each case constitutionally adapted to the climate, proves that acclimatization has occurred. But we have the same phenomenon in single varieties of man, such as the American, which inhabits alike the frozen wastes of Hudson's Bay and Tierra del Fuego, and the hottest regions of the tropics,—-the low equatorial valleys and the lofty plateaux of the Andes. No doubt a sudden transference to an extreme climate is often prejudicial to man, as it is to most animals and plants; but there is every reason to believe that, if the migration occurs step by step, man can be acclimatized to almost any part of the earth's surface in comparatively few generations. Some eminent writers have denied this. Sir Ranald Martin, from a consideration of the effects of the climate of India on Europeans and their offspring, believed that there is no such thing as acclimatization. Dr Hunt, in a report to the British Association in 1861, argued that "time is no agent,'' and—"if there is no sign of acclimatization in one generation, there is no such process.'' But he entirely ignored the effect of favourable variations, as well as the direct influence of climate acting on the organization from infancy.

Professor Theodor Waitz, in his Introduction to Anthropology, adduced many examples of the comparatively rapid constitutional adaptation of man to new climatic conditions. Negroes, for example,who have been for three or four generations acclimatized in North America, on returning to Africa become subject to the same local diseases as other unacclimatized individuals. He well remarked that the debility and sickening of Europeans in many tropical countries are wrongly ascribed to the climate, but are rather the consequences of indolence, sensual gratification and an irregular mode of life. Thus the English, who cannot give up animal food and spirituous liquors, are less able to sustain the heat of the tropics than the more sober Spaniards and Portuguese. The excessive mortality of European troops in India, and the delicacy of the children of European parents, do not affect the real question of acclimatization under proper conditions. They only show that acclimatization is in most cases necessary, not that it cannot take place. The best examples of partial or complete acclimatization are to be found where European races have permanently settled in the tropics, and have maintained themselves for several generations. There are, however, two sources of inaccuracy to be guarded against, and these are made the most of by the writers above referred to, and are supposed altogether to invalidate results which are otherwise opposed to their views. In the first place, we have the possibility of a mixture of native blood having occurred; in the second, there have almost always been a succession of immigrants from the parent country, who continually intermingle with the families of the early settlers. It is maintained that one or other of these mixtures is absolutely necessary to enable Europeans to continue long to flourish in the tropics.

There are, however, certain cases in which the sources of error above mentioned are reduced to a minimum, and cannot seriously affect the results; such as those of the Jews, the Dutch at the Cape of Good Hope and in the Moluccas, and the Spaniards in South America.

The Jews are a good example of acclimatization, because they have been established for many centuries in climates very different from that of their native land; they keep themselves almost wholly free from intermixture with the people around them; and they are often so populous in a country that the intermixture with Jewish immigrants from other lands cannot seriously affect the local purity of the race. They have, for instance, attained a population of millions in such severe climates as Poland and Russia; in the towns of Algeria they have succeeded so conspicuously as to bring about an outburst of anti-semitism; and in Cochin-China and Aden they succeed in rearing children and forming permanent communities.

In some of the hottest parts of South America Europeans are perfectly acclimatized, and where the race is kept pure it seems to be even improved. Some very valuable notes on this subject were furnished to the present writer by the well-known botanist, Richard Spruce, who resided many years in South America, but who was prevented by ill health from publishing his researches (see A. R. Wallace, Notes of a Botannist, 1908). As a careful, judicious and accurate observer, both of man and nature, he had few superiors. He says:

The white inhabitants of Guayaquil (lat. 2 deg. 13' S.) are kept pure by careful selection. The slightest tincture of red or black blood bars entry into any of the old families who are descendants of Spaniards ftom the Provincias Vascongadas or those bordering the Bay of Biscay, where the morals are perhaps the purest (as regards the intercourse of the sexes) of any in Europe, and where for a girl, even of the poorest class, to have a child before marriage is the rarest thing possible. The consequence of this careful breeding is, that the women of Guavaquil are considered (and justly) the finest along the whole Pacific coast. They are often tall, sometimes very handsome, decidedly healthy, although pale, and assuredly prolific enough. Their sons are big, stout men, but when they lead inactive lives are apt to become fat and sluggish. Those of them, however, who have farms in the savannahs and are accustomed to take long rides in all weathers, and those whose trade obliges them to take frequent journeys in the mountainous interior, or even to Europe and North America, are often as active and as little burdened with superfluous flesh as a Scotch farmer.

The oldest Christian town in Peru is Piura (lat. 5 deg. S.), which was founded by Pizarro himself. The climate is very hot, especially in the three or four months following the southern solstice. In March 1843 the temperature only once fell as low as 83 deg. during the whole month, the usual lowest night temperature being 85 deg. . Yet people of all colours find it very healthy, and the whites are very prolific. I resided in the town itself nine months, and in the neighbourhood seven months more. The population (in 1863-1864) was about 10,000, of which not only a considerable proportion was white, but was mostly descended from the first emigrants after the conquest. Purity of descent was not, however, quite so strictly maintained as at Guayaquil. The military adventurers, who have often risen to high or even supreme rank in Peru, have not seldom been of mixed race, and fear or favour has often availed to procure them an alliance with the oldest and purest-blooded families.

These instances, so well stated by Spruce, seem to demonstrate the complete acclimatization of Spaniards in some of the hottest parts of South America. Although we have here nothiog to do with mixed races, yet the want of fertility in these has been often taken to be a fact inherent in the mongrel race, and has been also sometimes held to prove that neither the European nor his half-bred offspring can maintain themselves in the tropics. The following observation is therefore of interest:—

At Guayaquil for a lady of good family—-married or unmarried—to be of loose morals is so uncommon, that when it does happen it is felt as a calamity by the whole community. But here, and perhaps in most other towns in South America, a poor girl of mixed race-especially if good-looking—rarely thinks of marrying one of her own class until she has—as the Brazilians say—"approveitada de sua mocidade'' (made the most of her youth) in receiving presents from gentlemen. If she thus bring a good dowry to her husband, he does not care to inquire, or is not sensitive, about the mode in which it was acquired. The consequence of this indiscriminate sexual intercourse, especially if much prolonged, is to diminish, in some cases to paralyse, the fertility of the female. And as among people of mixed race it is almost universal, the population of these must fall off both in numbers and quality.