·Discovery and Exploration.-Albert Nyanza was first reached by Sir Samuel Baker on the 14th of March 1864 near Vacovia, a small village of fishermen and salt-makers on the east coast. From a granitic cliff 1500 ft. above the water he looked out over a boundless horizon on the south and south-west, and towards the west descried at a distance of 50 or 60 m. mountains about 7000 ft. high. Albert Nyanza was consequently entered on his map as a vast lake extending about 380 m. But the circumnavigation of the lake by Gessi Pasha (1876), and by Emin Pasha in 1884, showed that Baker had been deceived as to the size of the lake. By the end of the 19th century the topography of the lake region was known with fair accuracy. The lake forms part of the (British) Uganda Protectorate, but the north-west shores were leased in 1894 to the Congo Free State during the sovereignty of king Leopold II. of Belgium. Of this leased area a strip 15 m. wide, giving the Congo State a passage way to the lake, was to remain in its possession after the determination of the lease.

See Nile; Sir W. Garstin's Report upon the Basin of the Upper Nile (Egypt, No. 2, 1904); Capt. H. G. Lyons' The Physiography of the River Nile and its Basin (Cairo, 1906), and the authorities quoted in those works. (W. E. G.; F. R. C.) ALBERTUS MAGNUS (ALBERT OF COLOGNE, ?1206-1280), count of Bollstädt, scholastic philosopher, was born of the noble family of Bollstädt at Lauingen in Suabia. The date of his birth, generally given as 1193, is more probably 1206. He was educated principally at Padua, where he received instruction in Aristotle's writings. In 1223 (or 1221) he became a member of the Dominican order, and studied theology under its rules at Bologna and elsewhere. Selected to fill the position of lecturer at Cologne, where the order had a house, he taught for several years there, at Regensburg, Freiburg, Strassburg and Hildesheim. In 1245 he went to Paris, received his doctorate and taught for some time, in accordance with the regulations, with great success. In 1254 he was made provincial of his order, and fulfilled the arduous duties of the office with great care and efficiency. During the time he held this office he publicly defended the Dominicans against the university of Paris, commented on St John, and answered the errors of the Arabian philosopher, Averroes. In 1260 the pope made him bishop of Regensburg, which office he resigned after The remainder of his life he spent partly in preaching throughout Bavaria and the adjoining districts, partly in retirement in the various houses of his order; in 1270 he preached the eighth Crusade in Austria; almost the last of his labours was the defence of the orthodoxy of his former pupil, Thomas Aquinas. He died in 1280, aged seventy-four. He was beatified in 1622, and he is commemorated on the 16th of November. Albert's works (published in twenty-one folios by the Dominican Pierre Jammy in 1651, and reproduced by the Abbé Borgnet, Paris, 1890, 36 vols.) sufficiently attest his great activity. He was the most widely read and most learned man of his time. The whole of Aristotle's works, presented in the Latin translations and notes of the Arabian commentators, were by him digested, interpreted and systematized in accordance with church doctrine. Albert's activity, however, was rather philosophical than theological (see SCHOLASTICISM). The philosophical works, occupying the first six and the last of the twenty-one volumes, are generally divided according to the Aristotelian scheme of the sciences, and consist of interpretations and condensations of Aristotle's relative works, with supplementary discussions depending on the questions then agitated, and occasionally divergences from the

three years.

commentary in three volumes on the Books of the Sentences of Peter Lombard (Magister Sententiarum), and the Summa Theologiae in two volumes. This last is in substance a repetition of the first in a more didactic form. Albert's knowledge of physical science was considerable and for the age accurate. His industry in every department was great, and though we find in his system many of those gaps which are characteristic of scholastic philosophy, yet the protracted study of Aristotle gave him a great power of systematic thought and exposition, and the results of that study, as left to us, by no means warrant the contemptuous title sometimes given him-the "Ape of Aristotle." They rather lead us to appreciate the motives which caused his contemporaries to bestow on him the honourable surnames "The Great " and "Doctor Universalis." It must, however, be admitted that much of his knowledge was ill digested; it even appears that he regarded Plato and Speusippus as Stoics. Albertus is frequently mentioned by Dante, who made his doctrine of free-will the basis of his ethical system. Dante places him with his pupil Aquinas among the great lovers of wisdom (Spiriti Sapienti) in the Heaven of the Sun.

See Paget Toynbee, "Some Obligations of Dante to Albertus Magnus in Romania, xxiv. 400-412, and the Dante Dictionary by the same author. For Albert's life see J. Sighart, Albertus Magnus, sein Leben und seine Wissenschaft (Regensburg, 1857; Eng. trans., Dixon, London, 1876); H. Finke, Ungedrückte Dominikanerbriefe des 13. Jahrh. (Paderborn, 1891). For his philosophy A. Stöckl, Geschichte d. scholastischen Philosophie; J. E. Erdmann, Grundriss d. Ges. d. Phil. vol. i. 8. The histories of Hauréau, Ritter, Prantl and Windelband may also be consulted. See also W. Feiler, Die Moral d. A. M. (Leipzig, 1891); M. Weiss, Ueber mariologische Schriften des A. M. (Paris, 1898); Jos. Bach, Des A. M. Verhältniss zu d. Erkenntnisslehre d. Griechen, Römer, Araber u. Juden (Vienna, 1881); Herzog-Hauck, Realencyk. (1897); Vacant, Dict. Theol. Cathol. (s.v.); Ch. Jourdain in Dict. d. sciences philos. (s.v.); M. Joel, Das Verhältniss A. d. G. zu Moses Maimonides (Breslau, 1863).

ALBERUS, ERASMUS (c. 1500-1553), German humanist, reformer and poet, was a native of the village of Sprendlingen near Frankfort-on-Main, where he was born about the year 1500. Although his father was a schoolmaster, his early education was neglected. Ultimately in 1518 he found his way to the university of Wittenberg, where he studied theology. He had here the good fortune to attract the attention of Luther and Melanchthon, and subsequently became one of Luther's most active helpers in the Reformation. Not merely did he fight for the Protestant cause as a preacher and theologian, but he was almost the only member of Luther's party who was able to confront the Roman Catholics with the weapon of literary satire. In 1542 he published a prose satire to which Luther wrote the preface, Der Barfüsser Mönche Eulenspiegel und Alkoran, an adaptation of the Liber conformitatum of the Franciscan Bartolommeo Albizzi of Pisa (Pisanus, d. 1401), in which the Franciscan order is held up to ridicule. Of higher literary value is the didactic and satirical Buch von der Tugend und Weisheit (1550), a collection of fortynine fables in which Alberus embodies his views on the relations of Church and State. His satire is incisive, but in a scholarly and humanistic way; it does not appeal to popular passions with the fierce directness which enabled the master of Catholic satire, Thomas Murner, to inflict such telling blows. Several of Alberus's hymns, all of which show the influence of his master Luther, have been retained in the German Protestant hymnal. After Luther's death, Alberus was for a time Diakonus in Wittenberg; he became involved, however, in the political conflicts of the time, and was in Magdeburg in 1550-1551, while that town was besieged by Maurice of Saxony. In 1552 he was appointed Generalsuperintendent at Neubrandenburg in Mecklenburg, where he died on the 5th of May 1553.

Das Buch von der Tugend und Weisheit has been edited by W. Braune (1892); the sixteen Geistliche Lieder by C. W. Stromberger (1857). Alberus's prose writings have not been reprinted in recent times. See F. Schnorr von Carolsfeld, Erasmus Alberus (1894).

ALBERY, JAMES (1838-1889), English dramatist, was born in London on the 4th of May 1838. On leaving school he entered an architect's office, and started to write plays. After many failures he at last succeeded in getting an adaptation-Dr Davy

in which Sir Henry Irving made one of his earliest London successes as Digby Grant. He was the author of a large number of other plays and adaptations, including Jingle (a version of Pickwick), produced at the Lyceum in 1878, and Pink Dominoes, the latter being one of a series of adaptations from the French which he made for the Criterion theatre. At that house his wife, the well-known actress, Miss Mary Moore, played the leading parts. He died on the 15th of August 1889.

ALBI, a city of south-western France, capital of the department of Tarn, 48 m. N. E. of Toulouse, on ~ branch line of the Southern railway. Pop. (1906) 14,956. Albi occupies a commanding position on the left bank of the Tarn; it is united to its suburb of La Madeleine on the right bank by a medieval and a modern bridge. The old town forms a nucleus of narrow, winding streets surrounded by boulevards, beyond which lie modern quarters with regular thoroughfares and public gardens. The cathedral of Sainte Cécile, a fine fortress-church in the Gothic style, begun in 1277, finished in 1512, rises high above the rest of the town. The exterior, flanked at the western end by a lofty tower and pierced by high, narrow windows, is devoid of ornament. Its general plainness contrasts with the elaborate carving of the stone canopy which shelters the southern portal. In the interior, which is without transepts or aisles, the roodscreen and the choir-enclosure, which date from about 1500, are masterpieces of delicate sculpture; the vaulting and the walls are covered with paintings of the 15th and 16th centuries. The archbishop's palace to the north-east of the cathedral is a fortified building of the 14th century. St Salvi, the chief of the other churches of Albi, belongs to the 13th and 15th centuries. A statue of the sailor La Pérouse (1741-1788) stands in the square named after him.

Albi is the seat of an archbishop, a prefect and a court of assizes. It has tribunals of first instance and of commerce, a board of trade-arbitrators, a chamber of commerce, a lycée and training colleges. The industrial establishments of the town include dye-works, distilleries, tanneries, glass-works and important flour-mills. It is also a centre for hat-making, and produces cloth-fabrics, lace, umbrellas, casks, chairs, wooden shoes, candles and pastries. Trade is in wine and anise.

Albi (Albiga) was, in the Gallo-Roman period, capital of the Albigenses, and later of the viscounty of Albigeois, which was a fief of the counts of Toulouse. From the 12th century onwards, its bishops, the first of whom appears to have lived about the 3rd century, began to encroach on the authority of the viscounts; the latter, after the Albigensian war, lost their estates, which passed to Simon de Montfort and then to the crown of France. By a convention concluded in 1264 the chief temporal power in the city was granted to the bishops. The archbishopric dates from 1678.

=

ALBIAN (Fr. Albien, from Alba Aube in France), in geology the term proposed in 1842 by A. d'Orbigny for that stage of the Cretaceous System which comes above the Aptian and below the Cenomanian (Pal. France. Crét. ii.). The precise limits of this stage are placed somewhat differently by English and continental geologists. In England it is usual to regard the Albian stage as equivalent to the Upper Greensand plus Gault, that is, to the "Selbornian" of Jukes-Browne. But A. de Lapparent would place most of the Upper Greensand in the Cenomanian. The English practice is to commence the upper Cretaceous with the Albian; on the other hand, this stage closes the lower Cretaceous according to continental usage. It is necessary therefore, when using the term Albian, to bear these differences in mind, and to ascertain the exact position of the strata by reference to the zonal fossils. These are, in descending order, Pecten asper and Cardiaster fossarius, Schloenbachia rostrata, Hoplites lautus and H. interruptus, Douvilleiceras mammillatum. In addition to the formations mentioned above, the following representatives of the Albian stage are worthy of notice: the gaize and phosphatic beds of Argonne and Bray in France; the Flammenmergel of North Germany; the lignites of

See GAULT, GREENSAND, and CRETACEOUS. (J. A. H.) ALBIGENSES, the usual designation of the heretics-and more especially the Catharist heretics-of the south of France in the 12th and 13th centuries. This name appears to have been given to them at the end of the 12th century, and was used in 1181 by the chronicler Geoffroy de Vigeois. The designation is hardly exact, for the heretical centre was at Toulouse and in the neighbouring districts rather than at Albi (the ancient Albiga). The heresy, which had penetrated into these regions probably by trade routes, came originally from eastern Europe. The name of Bulgarians (Bougres) was often applied to the Albigenses, and they always kept up intercourse with the Bogomil sectaries of Thrace. Their dualist doctrines, as described by controversialists, present numerous resemblances to those of the Bogomils, and still more to those of the Paulicians, with whom they are sometimes connected. It is exceedingly difficult, however, to form any very precise idea of the Albigensian doctrines, as our knowledge of them is derived from their opponents, and the very rare texts emanating from the Albigenses which have come down to us (e.g. the Rituel cathare de Lyon and the Nouveau Testament en provençal) contain very inadequate information concerning their metaphysical principles and moral practice. What is certain is that, above all, they formed an anti-sacerdotal party in permanent opposition to the Roman church, and raised a continued protest against the corruption of + clergy of their time. The Albigensian theologians and ascetics, the Cathari or perfecti, known in the south of France as bons hommes or bons chrétiens, were few in number; the mass of believers (credentes) were perhaps not initiated into the Catharist doctrine; at all events, they were free from all moral prohibition and all religious obligation, on condition that they promised by an act called convenenza to become "hereticized" by receiving the consolamentum, the baptism of the Spirit, before their death or even in extremis.

The first Catharist heretics appeared in Limousin between IO12 and 1020. Several were discovered and put to death at Toulouse in 1022; and the synod of Charroux (dep. of Vienne) in 1028, and that of Toulouse in 1056, condemned the growing sect. The preachers Raoul Ardent in 1101 and Robert of Arbrissel in 1114 were summoned to the districts of the Agenais and the Toulousain to combat the heretical propaganda. But, protected by William IX., duke of Aquitaine, and soon by a great part of the southern nobility, the heretics gained ground in the south, and in 1119 the council of Toulouse in vain ordered the secular powers to assist the ecclesiastical authority in quelling the heresy. The people were attached to the bons hommes, whose asceticism imposed upon the masses, and the anti-sacerdotal preaching of Peter of Bruys and Henry of Lausanne in Périgord, Languedoc and Provence, only facilitated the progress of Catharism in those regions. In 1147 Pope Eugenius III. sent the legate Alberic of Ostia and St Bernard to the affected district. The few isolated successes of the abbot of Clairvaux could not obscure the real results of this mission, and the meeting at Lombers in 1165 of a synod, where Catholic priests had to submit to a discussion with Catharist doctors, well shows the power of the sect in the south of France at that period. Moreover, two years afterwards a Catharist synod, in which heretics from Languedoc, Bulgaria and Italy took part, was held at St Félix de Caraman, near Toulouse, and their deliberations were undisturbed. The missions of Cardinal Peter (of St Chrysogonus), formerly bishop of Meaux, to Toulouse and the Toulousain in 1178, and of Henry, cardinal-bishop of Albano (formerly abbot of Clairvaux), in 1180-1181, obtained merely momentary successes. Henry of Albano attempted an armed expedition against the stronghold of heretics at Lavaur and against Raymond Roger, viscount of Béziers, their acknowledged protector. The taking of Lavaur and the submission of Raymond Roger in no way arrested the progress of the heresy. The persistent decisions of the councils against the heretics at this period-in particular, those of the council of Tours (1163) and of the oecumenical

Lateran council (1179)-had scarcely more effect. But on ascending the papal throne, Innocent III. resolved to suppress the Albigenses. At first he tried pacific conversion, and in 1198 and 1199 sent into the affected regions two Cistercian monks, Regnier and Guy, and in 1203 two monks of Fontfroide, Peter of Castelnau and Raoul (Ralph), with whom in 1204 he even associated the Cistercian abbot, Arnaud (Arnold). They had to contend not only with the heretics, the nobles who protected them, and the people who listened to them and venerated them, but also with the bishops of the district, who rejected the extraordinary authority which the pope had conferred upon his legates, the monks. In 1204 Innocent III. suspended the authority of the bishops of the south of France. Peter of Castelnau retaliated by excommunicating Raymond VI., count of Toulouse, as an abettor of heresy (1207), and kindled in the nobles of the south that animosity of which he was the first victim (1209). As soon as he heard of the murder of Peter of Castelnau, the pope ordered the Cistercians to preach the crusade against the Albigenses. This implacable war, which threw the whole of the nobility of the north of France against that of the south, and destroyed the brilliant Provençal civilization, ended, politically, in the treaty of Paris (1229), by which the king of France dispossessed the house of Toulouse of the greater part of its fiefs, and that of Béziers of the whole of its fiefs. The independence of the princes of the south was at an end, but, so far as the heresy was concerned, Albigensianism was not extinguished, in spite of the wholesale massacres of heretics during the war. Raymond VII. of Toulouse and the count of Foix gave asylum to the "faidits" (proscribed), and the people were averse from handing over the bons hommes. The Inquisition, however, operating unremittingly in the south at Toulouse, Albi, Carcassonne and other towns during the whole of the 13th century and a great part of the 14th, succeeded in crushing the heresy. There were indeed some outbursts of rebellion, some fomented by the nobles of Languedoc (12401242), and others emanating from the people of the towns, who were embittered by confiscations and religious persecutions (e.g. at Narbonne in 1234 and Toulouse in 1235), but the repressive measures were terrible. In 1245 the royal officers assisting the Inquisition seized the heretical citadel of Montségur, and 200 Cathari were burned in one day. Moreover, the church decreed severe chastisement against all laymen suspected of sympathy with the heretics (council of Narbonne, 1235; Bull Ad extirpanda, 1252).

Hunted down by the Inquisition and quickly abandoned by the nobles of the district, the Albigenses became more and more scattered, hiding in the forests and mountains, and only meeting surreptitiously. There were some recrudescences of heresy, such as that produced by the preaching (1298-1309) of the Catharist minister, Pierre Authier; the people, too, made some attempts to throw off the yoke of the Inquisition and the French,1 and insurrections broke out under the leadership of Bernard of Foix, Aimery of Narbonne, and, especially, Bernard Delicieux at the beginning of the 14th century. But at this point vast inquests were set on foot by the Inquisition, which terrorized the district. Precise indications of these are found in the registers of the Inquisitors, Bernard of Caux, Jean de St Pierre, Geoffroy d'Ablis, and others. The sect, moreover, was exhausted and could find no more adepts in a district which, by fair means or foul, had arrived at a state of peace and political and religious unity. After 1330 the records of the Inquisition contain but few proceedings against Catharists. (See also under CATHARS.) AUTHORITIES.-See C. Schmidt's Histoire de la secte des Cathares ou Albigeois (Paris, 1849), which is still the most important work on the subject. The following will be found useful: D. Vaissete, Histoire de Languedoc, vols. iii. iv. vii. viii. (new edition); Ch. Molinier, L'Inquisition dans le Midi de la France (Paris, 1880), and the other works by the same author; L. Tanon, Histoire des tribunaux de l'Inquisition en France (Paris, 1893). Les Albigeois, leurs origines (Paris, 1878), by Douais, should be read with caution. Of the sources, which are very numerous, may be mentioned: the Liber Sententiarum

1 These they often confounded, and a heretic is described as saying: Clergy and French, they are one and the same thing."

of the Inquisition of Carcassonne, published by Ph. van Limborch registers of the Inquisition analysed at length by Ch. Molinier, at the end of his Historia Inquisitionis (Amsterdam, 1692); other op. cit., some published in vol. ii. of the Documents pour l'histoire de l'Inquisition (Paris, 1900), by C. Douais; numerous texts concerning the last days of Albigensianism, collected by M. Vidal, "Les derniers ministres albigeois,' in Rev. de quest. histor. (1906). See also the Rituel cathare, ed. by Cunitz (Jenā, 1852); the Nouveau Testament en provençal, ed. by Clédat (Paris, 1887); and the very curious Débat d'Yzarn et de Sicart de Figueiras, ed. by P. Meyer (1880). On the ethics of the Catharists, see Jean Guiraud, Questions d'histoire et d'archéologie chrétienne (Paris, 1906); and P. Alphandéry, Les idées morales chez les hétérodoxes latins au début du XIIIe siècle (Paris, 1903). (P. A.)

race.

ALBINO, a biological term (Lat. albus, white), in the usual acceptation, for a pigmentless individual of a normally pigmented Among some flowering plants, however, the character has become one of specific rank, and among animals we have in the polar bear and the Greenland hare instances where partial albinism-for in them the eyes are black and other parts may be pigmented-has also become a specific character.

A true or complete albino is altogether devoid of pigment. One result of this among the Vertebrata is that the eyeball is pink in colour, since the cornea, iris and retina being transparent, the red blood contained in the capillaries is unmasked by the absence of pigmentary material. In man, and doubtless also in lower forms, the absence of this pigment produces the wellmarked albinotic facies. This is a condition in which the eyelids are brought into a nearly closed position accompanied by blinking movements and a general wrinkling of the skin around the immediate neighbourhood of the eyes. It is the result of the too great intensity of the light incident upon the retina, and which in normal eyeballs is adequately diminished by the absorptive power of the pigmentary material.

In a complete albino not only is all pigment absent in the skin, but also that which is normally present in deeper organs, such as the sympathetic nervous system and in the substantia nigra of the brain. There is some reason to believe that a peculiar condition found in the majority of human albinoes, and known as nystagmus, is correlated with the absence of pigment in the central nervous system. This condition is one marked by unsteadiness-a sort of flickering rolling of the eyeballs, and it becomes more marked as they endeavour to adjust their accommodation to near objects. It is thought to depend upon some connexion, not yet anatomically demonstrated, between the third cranial nerve and its nucleus in the floor of the iter

and the substantia nigra.

coat.

In addition to complete albinism, there exist, however, various albinotic conditions in which more or less pigment may be present. Familiar instances of this partial albinism is seen in the domestic breed of Himalayan rabbits. In these animals the eyeball and the fur of the body are unpigmented, but the tips of the ear pinnae and extremities of the fore and hind limbs, together with the tail, are marked by more or less well defined colour. One remarkable feature of these animals is that for a few months after birth they are complete albinoes. Occasionally, however, some are born with a grey colour and a few may be quite black, but ultimately they attain their characteristic There is some reason to believe, as we shall see later, that in spite of the presence of a little pigment and of occasional wholly pigmented young ones, Himalayans must be regarded as true albinoes. Other individual rabbits, but belonging to no particular breed, are similarly marked, but in addition the eyeballs are black. Some domesticated mice are entirely white with the exception that they have black eyeballs; and individuals of this type are known in which there is a reduction of pigment in the eyeballs, and since the colour of the blood is then partially visible these appear of a reddish-black colour. Such cases are interesting as representing the last step in the graded series through which the condition of complete pigmentation passes into that of complete albinism.

There is evidence, as shown by G. M. Allen, that partial albinism is a condition in which pigment is reduced around definite body centres, so that unpigmented areas occur between

the pigment patches or at their borders. In the mouse, ten such centres may be distinguished, arranged symmetrically five on either side of the median plane-a cheek patch, neck patch, shoulder patch, side patch and rump patch. Various degrees in the reduction of the pigment patches up to that of complete elimination may be traced.

Some animals are wholly pigmented during the summer and autumn, but through the winter and spring they are in the condition of extreme partial albinism and become almost complete albinoes. Such instances are found in the Scotch blue hare (Lepus timidus), in the Norway, hare, in the North American hare (L. americanus), in the arctic fox (Canis lagopus), in the stoat and ermine, and among birds, in the ptarmigan, and some other species of Lagopus. How the change from the autumnal to the winter condition takes place appears not to be definitely settled in all cases, and accurate observations are much to be desired. In the case of the Norway hare, it has been stated that a general moult, including all the hairs and under fur, takes place and new white hairs are substituted. The process of moulting is said to begin in the middle of autumn and is completed before the end of December, by which time the fur is in its winter condition, and is closer, fuller and longer than in summer (Naturalists' Library, vol. vii.). On the other hand, it has been stated that during the whole of the transformation in the fur no hairs fall from the animal, and it is attributed to an actual change in the colour of the hair (Edinburgh Philosophical Journal, vol. xi. p. 191). In the case of the American hare, however, some very careful observations have been made by F. H. Welch. In this animal the long hairs (which form the pile) become white at their extremities, and in some of them this whiteness extends through their whole length. At the same time, new hairs begin to develop and to grow rapidly, and soon outstrip the hairs of the autumn pile. From their first appearance these new hairs are, white and stiff, and they are confined to the sides and back of the body. It is not clear from Welch's account what is the cause of the whiteness of the tips of the hairs of the autumn coat, but his figures suggest that it is due to the development of gas in the interspaces between the keratin bridges and trabeculae of the hairs. There is nothing to show whether the pigment persists or is absorbed. Probably it persists. In this event, the whiteness of the tips will be due to the scattering or irregular reflexion of the incident rays of light from the surface of the numerous gas bubbles. In the case of the ptarmigan the evidence is clear that the existing autumnal feathers do change, more or less completely, to white. But the evidence is not conclusive as to whether any part of the winter condition is additionally produced by moulting..

The condition of albinism thus assumed as a seasonal variation is never complete, for the eyes at least retain their pigmented state. The reason of this is readily understood when it is borne in mind how disadvantageous to the function of sight is the unpigmented condition of an albino's eyeball; a disadvantage which would be probably much accentuated, in the cases now under consideration, by the bright glare from the surface of the snow, which forms the natural environment of these animals at the particular period of the year when the winter change occurs. In some cases, as in all the varying hares, in addition to the eyes retaining their normal pigmentation, areas similar in extent and situation to those on the Himalayan rabbits also retain their pigmentation; and in the ptarmigan there is a black band on each side of the head stretching forwards and backwards from the eyeball, and the outer tail feathers are black.

Albinism is restricted to no particular class of the animal kingdom; for partial albinism at least is known to occur in Coelentera, worms, Crustacea, Myriapoda, Coleoptera, Arachnida and fishes. The individuals in which this diminished pigmentation is found are for the most part those living in caves, and it is probable that their condition is not truly albinotic, but only temporary and due to the absence of the stimulus of light. This may be also true of some of those instances that have occurred among frogs, in Proteus, and with an axolotl

once possessed by the present writer. This latter animal was quite white, with the exception of the black eyeballs. At the end of four weeks after it was first purchased the dorsal cr upper surface of its external gills developed a small amount of dark pigment. Within the next few weeks this increased in quantity and the dorsal surface of the head and of the front end of the trunk began to be pigmented. The animal died at the end of the eighth week, but it is possible that had it lived it would have become wholly pigmented. But, apart from these instances, albinism is known, according to W. E. Castle, who cites it on the authority of Hugh M. Smith, to occur among a breed of albino trout, which breed true and are reared in the State fish-hatcheries of America. With birds and mammals, however, there is no doubt that complete albino individuals do occur; and among species which, like the jackdaw, certain deer and rabbits, are normally deeply pigmented.

Albinism occurs in all races of mankind, among mountainous as well as lowland dwellers. And, with man, as with other animals, it may be complete or partial. Instances of the latter condition are very common among the negroes of the United States and of South America, and in them assumes a piebald character, irregular white patches being scattered over the general black surface of the body. Occasionally the piebald patches tend to be symmetrically arranged, and sometimes the eyeballs are pigmentless (pink) and sometimes pigmented (black). According to A. R. Gunn, of Edinburgh University, who has recently been investigating the subject of albinism in man, there is reason to believe that a condition of piebald albinism occurs also in Europeans (Scotsmen). He has examined subjects in which the whole of the hair of the body is white, but the eyeballs are pigmented, often deeply; and, conversely, he has seen cases in which the eyes are pink but the hair is pigmented. The hair and the eyes may be regarded as skin patches, in which sometimes the one and sometimes the other is pigmentless. He believes that, were it not for the generally very pale colour of white-skinned races, this piebald condition would be as manifest in them as in negroes, over the whole surface of the body.

In complete human albinoes, albinism is correlated, in addition to nystagmus, with a peculiar roughness of the skin, making it harsh to the touch. The skin is also milky-white in appearance. According to C. J. Seligmann, there exists among the Papuans an albinotic race whose skin varies in colour from a pink-white to that of café au lait; the eyes are generally greenish, hazel or brown, and the hair is tow-coloured. The skin where unexposed is pinker than that of a normal North European. Like complete albinoes, this race suffers from photophobia, and is characterized by the albinotic facies.

Before we can inquire into the cause and meaning of albinism it will be necessary first to consider the nature of pigmentation. It has recently been ascertained that the coloration of certain sponges is due to the interaction of an oxydizing ferment, tyrosinase, upon certain colourless chromogenic substances. In 1901, Otto v. Furth and Hugo Schneider showed that a tyrosinase could be obtained from the blood of certain insects, and, acting upon a chromogen present in the blood, converted it into a pigmentary substance of melanin-like nature. Hans Przibram also extracted a tyrosinase from the ink-sac of Sepia, and, causing it to act upon a watery solution of tyrosin, obtained a black pigment. From the blood of Bombyx mori, V. von Ducceshi has also obtained a tyrosinase.

Subsequently (1903) L. Cuénot, in order to explain certain features in the hereditary transmission of coat colour in mice, postulated the hypothesis that the grey colour of the wild mouse (which is known to be a compound of black, chocolate and yellow pigments) may be due either to the interaction of a single ferment and three chromogens, or vice versa, to one chromogenic substance and three ferments.

Since then (1904) Miss Florence Durham has shown that if the skins of young or embryonic mammals (rats, rabbits and guinea-pigs) be ground up and extracted in water, and the expressed juice be then incubated with solid tyrosin for twentyfour hours, with the addition of a very small amount of ferrous

sulphate to act as an activator, a pigmentary substance is thrown down. The colour of this substance is that of the pigment in the skin or hairs of the animal used. Miss Durham interprets her results as indicating that the skin of these pigmented animals normally secretes one or more tyrosinases. The same result was obtained from the skins of some unhatched chickens. The skins of albinoes gave no results.

Not only have such resuits been obtained with sponges, insects, cephalopods, birds and mammals, but Em. Bourquelot and G. Bertrand have shown that certain fungi, the tissues of which, when exposed to the air by injury, become immediately coloured, do so owing to the action of tyrosinase upon one or more chromogenous substances present in the plant. We may conceive, then, that a pigmented animal owes its colour to the power that certain tissues of its body possess to secrete both tyrosinases and chromogenic substances. And the period at which this process is most active is at birth, or preceding it or immediately succeeding it. In spite of the inquiry being only in its initial stages, there is already good evidence to believe that Cuénot's theory is correct, and that an albino is an individual whose skin lacks the power to secrete either the ferment or the chromogen. It forms one but not both of these substances.

A moment's consideration, however, will show that, while an albino may be an individual in which one or more of the complementary bodies of pigmentation are absent, a pigmented animal is something more than an individual which carries all the factors necessary for the development of colour. For it must be borne in mind that animals are not only coloured but the colour is arranged in a more or less definite pattern. The wild mouse, rat and rabbit are self-coloured, but the domesticated forms include various piebald patterns, such as spotted forms among mice, and the familiar black and white hooded and dorsal-striped pattern of some tame rats.

Colour, therefore, must be correlated with some determinant (determining factor) for pattern, and it cannot, therefore, exist alone in an animal's coat. And we must conceive that each kind of pattern-the self, the spotted, the striped, the hooded and all others has its own special determinant. Given the presence of all the necessary determinants for the development of pigment in a mammal's coat, some or all of the hairs may bear this pigment according to the pattern determinants, or absence of pattern determinants, which the cells of the hair papillae carry. And this brings us to the question as to whether in a piebald animal the pigmented hairs are in any way different from the pigmentless or white hairs. No adequate investigation of this subject has yet been made, but some observations made by the author of this article, on the piebald black and white rat, show that differences connected with the microscopic structure exist. There is thus evidence that colour is correlated with other factors which determine pattern. And this leads to the inquiry as to whether albinoes ever exhibit evidence that they carry the pattern determinants in the absence of those for pigmentation. For it is to be expected a priori that, since albinoes were derived from pigmented progenitors and may at any time appear, side by side with pigmented brothers, in a litter from pigmented parents, they would be carrying the pattern determinants of some one or other of their pigmented ancestors. Now we know, from the numerous experiments in heredity which have resulted since the rediscovery of Mendel's principles, that an individual may carry a character in one of two conditions. It may be carried as a somatic character, when it will be visible in the body tissues, or it may be carried as a gametic character, and its presence can only then be detected in subsequent generations, by adequately devised breeding tests.

With regard to pattern, the evidence is now clear that albinoes may carry the determinants in both these ways. So far as they are carried gametically, i.e. by the sex-cells, it has been shown by Cuénot and G. M. Allen for mice, by C. C. Hurst for rabbits, and by L. Doncaster and G. P. Mudge for rats, that in a cross between a coloured individual of known gametic purity and an albino, the individuals of the progeny in either the first or second, or both generations, may differ, and that the difference in some

cases wholly depends upon the albino used. It has been shown that the individuals in such an offspring may bear patterns which never occurred in the ancestry of the coloured parent, but did in that of the albino; and, moreover, if the same coloured parent be mated with another individual, either albino or coloured, that their offspring may never contain members bearing such patterns. The particular pattern will only appear when the coloured parent is mated with the particular albino. And yet the albino itself shows no somatic pattern or pigment. So clear is the evidence on this point that any one adequately acquainted at first hand with the phenomena, by employing an albino of known gametic structure and mating it with a coloured individual, also of known gametic constitution, could predict the result.

With respect to albinoes carrying pattern as a visible somatic character, i.e. in the body cells, no definite evidence has as yet been published. But W. Haacke has described a single albino rat, in which he states that the hairs of the shoulder and mid-dorsal regions were of a different texture from those of the rest of the body. And it is possible that this albino, had it developed colour, would have been of the piebald pattern. But the author of this article has quite recently reared some albinoes in which the familiar shoulder hood and dorsal stripe of the piebald rat is perfectly obvious, in spite of the absence of the slightest pigmentation. The hairs which occupy the region which in the pigmented individual is black, are longer, thinner and more widely separated than those in the regions which are white. As a result of this, the pink skin is quite visible where these hairs occur, but elsewhere it is invisible. Thus these albinoes exhibit a pattern of pink skin similar in form with the black pattern of the piebald rat. Moreover, some of the albinoes possess these particular "pattern" hairs all over the body and obviously such individuals are carrying the self pattern. There are other details into which we cannot here enter, but which support the interpretation put upon these facts, i.e. that these particular albinoes are carrying in the soma the pattern determinants simultaneously with the absence of some of the factors for pigmentation.

Not only do albinoes thus carry the determinants for pattern, but it has been known for some time that they also carry gametically, but never visible somatically, the determinants for either the ferment or the chromogen for one or more colours. L. Cuénot was the first to show this for albino mice. He was able by appropriate experiments to demonstrate that when an albino is derived (extracted) from a coloured ancestry, and is then crossed with a coloured individual, both the colour of the pigmented parent and of the pigmented ancestry of the albino may appear among the individuals of the offspring.

Immediately subsequent to Cuénot, G. M. Allen in America demonstrated the same fact upon the same species of rodents. C. C. Hurst, more recently, has shown that albino rabbits. whether pure bred for eight generations at least, or extracted from pigmented parents, may carry the determinants for black or for black and grey. In this latter case the determinants for black are carried by separate gametes from those carrying grey, and the two kinds of sex-cells exist in approximately equal numbers. This is likewise true of albino mice when they carry the determinants for more than one colour.

Since Hurst's work, L. Doncaster and G. P. Mudge have both shown that albino rats also carry in a latent condition the determinants for black or grey. determinants for black or grey. The experiments of the latter author show that, if a gametically pure black rat be crossed with an albino derived from a piebald black and white ancestry, all the offspring in successive litters will be black; but if the same black parent be crossed with albinoes extracted from parents of which one or both are grey, then both grey and black members will appear in the successive litters.

The proportions in which the various coloured individuals appear are approximately those demanded by the Mendelian principle of gametic purity and segregation. Cuénot and Hurst have also shown that when albinoes of one colour extraction are crossed with albinoes of another colour extraction the segregation of the colour determinants in the gametogenesis of the albinoes takes place in precisely the same way that it does in the